Everything was working normally, then I briefly lost internet connection. I logged to the Spitz dashboard and saw the cellular was disconnected. One minute later cellular connected to 3g. So it seems i witnessed that process when the router reconnects to 3g.
I am sending you the error logs starting when the cellular was down, and when it reconnected to 3g

equestSetupDataCall QMUXResult = 0x1, QMUXError = 0xe

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:07:58:048] call_end_reason is 1

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:07:58:048] call_end_reason_type is 2

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:07:58:048] call_end_reason_verbose is 210

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:07:58:048] try to requestSetupDataCall 60 second later

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:07:58:048] your sim card may not support ipv6, please contact your carrier

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:07:58:048] check whether the sim card has obtained an ipv6 address. AT command 'AT+CGPADDR'

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:14:759] requestQueryDataCall IPv4ConnectionStatus: DISCONNECTED

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:768] requestSetupDataCall QMUXResult = 0x1, QMUXError = 0xe

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:768] call_end_reason is 3

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:768] call_end_reason_type is 3

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:768] call_end_reason_verbose is 2001

Tue Apr 22 21:08:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:768] trying to get ipv6 address

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:776] requestSetupDataCall QMUXResult = 0x1, QMUXError = 0xe

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:776] call_end_reason is 3

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:776] call_end_reason_type is 3

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:776] call_end_reason_verbose is 2001

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:776] try to requestSetupDataCall 60 second later

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:776] your sim card may not support ipv6, please contact your carrier

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:15:776] check whether the sim card has obtained an ipv6 address. AT command 'AT+CGPADDR'

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:18:614] requestRegistrationState2 MCC: 219, MNC: 1, PS: Detached, DataCap: UNKNOW

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:33:631] requestRegistrationState2 MCC: 219, MNC: 1, PS: Detached, DataCap: UNKNOW

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:08:48:646] requestRegistrationState2 MCC: 219, MNC: 1, PS: Detached, DataCap: UNKNOW

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:03:656] requestRegistrationState2 MCC: 219, MNC: 1, PS: Detached, DataCap: UNKNOW

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:14:349] requestRegistrationState2 MCC: 219, MNC: 2, PS: Detached, DataCap: UNKNOW

Tue Apr 22 21:09:15 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:14:354] requestRegistrationState2 MCC: 219, MNC: 2, PS: Detached, DataCap: UNKNOW

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:121] requestRegistrationState2 MCC: 219, MNC: 2, PS: Attached, DataCap: LTE

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:130] requestSetupDataCall WdsConnectionIPv4Handle: 0xe289f4a0

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:135] trying to get ipv6 address

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:147] requestSetupDataCall QMUXResult = 0x1, QMUXError = 0xe

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:147] call_end_reason is 3

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:147] call_end_reason_type is 3

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:147] call_end_reason_verbose is 2001

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:147] try to requestSetupDataCall 60 second later

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:147] your sim card may not support ipv6, please contact your carrier

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:147] check whether the sim card has obtained an ipv6 address. AT command 'AT+CGPADDR'

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:150] requestRegistrationState2 MCC: 219, MNC: 2, PS: Attached, DataCap: LTE

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:15:153] requestQueryDataCall IPv4ConnectionStatus: DISCONNECTED

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:163] requestSetupDataCall QMUXResult = 0x1, QMUXError = 0xe

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:163] call_end_reason is 3

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:164] call_end_reason_type is 3

Tue Apr 22 21:09:16 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:164] call_end_reason_verbose is 2001

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:164] trying to get ipv6 address

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:173] requestSetupDataCall QMUXResult = 0x1, QMUXError = 0xe

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:173] call_end_reason is 3

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:173] call_end_reason_type is 3

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:173] call_end_reason_verbose is 2001

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:173] try to requestSetupDataCall 60 second later

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:173] your sim card may not support ipv6, please contact your carrier

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:174] check whether the sim card has obtained an ipv6 address. AT command 'AT+CGPADDR'

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:224] requestRegistrationState2 MCC: 219, MNC: 2, PS: Attached, DataCap: UMTS

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:16:227] requestRegistrationState2 MCC: 219, MNC: 2, PS: Attached, DataCap: UMTS

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:17:082] requestRegistrationState2 MCC: 219, MNC: 2, PS: Attached, DataCap: UMTS

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:17:660] requestRegistrationState2 MCC: 219, MNC: 2, PS: Attached, DataCap: UMTS

Tue Apr 22 21:10:19 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:09:18:129] requestRegistrationState2 MCC: 219, MNC: 2, PS: Attached, DataCap: UMTS

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:19:108] requestSetupDataCall WdsConnectionIPv4Handle: 0xe289f4a0

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:19:113] trying to get ipv6 address

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:19:119] requestSetupDataCall QMUXResult = 0x1, QMUXError = 0xe

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:19:119] call_end_reason is 1

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:19:119] call_end_reason_type is 2

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:19:119] call_end_reason_verbose is 210

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:19:119] try to requestSetupDataCall 60 second later

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:19:119] your sim card may not support ipv6, please contact your carrier

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:19:119] check whether the sim card has obtained an ipv6 address. AT command 'AT+CGPADDR'

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:19:122] requestRegistrationState2 MCC: 219, MNC: 2, PS: Attached, DataCap: UMTS

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:20:128] trying to get ipv6 address

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:20:134] requestSetupDataCall QMUXResult = 0x1, QMUXError = 0xe

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:20:134] call_end_reason is 1

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:20:134] call_end_reason_type is 2

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:20:134] call_end_reason_verbose is 210

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:20:134] try to requestSetupDataCall 60 second later

Tue Apr 22 21:10:20 2025 daemon.notice netifd: modem_0001 (12811): [04-22_21:10:20:134] your sim card may not support ipv6, please contact your carrier

Tue Apr 22 21:10:45 2025 user.notice root: modem ip different, now regain ip ...

Tue Apr 22 21:10:45 2025 daemon.notice netifd: Interface 'modem_0001_4' has lost the connection

Tue Apr 22 21:10:45 2025 daemon.warn dnsmasq[5718]: no servers found in /tmp/resolv.conf.d/resolv.conf.auto, will retry

Tue Apr 22 21:10:45 2025 daemon.notice netifd: Interface 'modem_0001_4' is now down

Tue Apr 22 21:10:45 2025 daemon.notice netifd: Interface 'modem_0001_4' is disabled

Tue Apr 22 21:10:45 2025 daemon.notice netifd: Interface 'modem_0001_4' is enabled

Tue Apr 22 21:10:45 2025 daemon.notice netifd: Interface 'modem_0001_4' is setting up now

Tue Apr 22 21:10:45 2025 daemon.notice netifd: modem_0001_4 (30334): udhcpc: started, v1.33.2

Tue Apr 22 21:10:45 2025 user.notice firewall: Reloading firewall due to ifdown of modem_0001_4 ()

Tue Apr 22 21:10:45 2025 daemon.notice netifd: modem_0001_4 (30334): udhcpc: sending discover

Tue Apr 22 21:10:45 2025 daemon.notice netifd: modem_0001_4 (30334): udhcpc: sending select for 10.52.109.222

Tue Apr 22 21:10:45 2025 daemon.notice netifd: modem_0001_4 (30334): udhcpc: lease of 10.52.109.222 obtained, lease time 7200

Tue Apr 22 21:10:45 2025 daemon.notice netifd: Interface 'modem_0001_4' is now up

Tue Apr 22 21:10:45 2025 daemon.info dnsmasq[5718]: reading /tmp/resolv.conf.d/resolv.conf.auto

Tue Apr 22 21:10:45 2025 daemon.info dnsmasq[5718]: using only locally-known addresses for domain test

Tue Apr 22 21:10:45 2025 daemon.info dnsmasq[5718]: using only locally-known addresses for domain onion

Tue Apr 22 21:10:45 2025 daemon.info dnsmasq[5718]: using only locally-known addresses for domain localhost

Tue Apr 22 21:10:45 2025 daemon.info dnsmasq[5718]: using only locally-known addresses for domain local

Tue Apr 22 21:10:45 2025 daemon.info dnsmasq[5718]: using only locally-known addresses for domain invalid

Tue Apr 22 21:10:45 2025 daemon.info dnsmasq[5718]: using only locally-known addresses for domain bind

Tue Apr 22 21:10:45 2025 daemon.info dnsmasq[5718]: using only locally-known addresses for domain lan

Tue Apr 22 21:10:45 2025 daemon.info dnsmasq[5718]: using nameserver 86.32.10.10#53

Tue Apr 22 21:10:45 2025 daemon.info dnsmasq[5718]: using nameserver 86.32.10.100#53

Tue Apr 22 21:10:46 2025 user.notice firewall: Reloading firewall due to ifup of modem_0001_4 (rmnet_mhi0)