GL-MT3000 Version 4.5.0 WGCLIENT Failed to parse json data

I am using wireguard client on GL-MT3000 from last few months and never had problem, last few days I am seeing issue that WG does connect initially but you can able to reach anything and eventually you see below messages:

Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547): Warning: fw3_ipt_rule_append(): Can't find match 'connmark'
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):    * Zone 'lan'
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):    * Zone 'wan'
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):    * Zone 'guest'
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):    * Zone 'wgclient'
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):  * Set tcp_ecn to off
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):  * Set tcp_syncookies to on
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):  * Set tcp_window_scaling to on
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):  * Running script '/etc/firewall.nat6'
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):  * Running script '/etc/firewall.swap_wan_in_conn_mark.sh'
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):  * Running script '/etc/firewall.vpn_server_policy.sh'
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):  * Running script '/var/etc/gls2s.include'
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):    ! Skipping due to path error: No such file or directory
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547):  * Running script '/usr/bin/gl_block.sh'
Tue Feb 20 10:27:00 2024 daemon.notice netifd: wgclient (26547): Failed to parse json data: unexpected character
Tue Feb 20 10:27:00 2024 daemon.notice netifd: Network device 'wgclient' link is down
Tue Feb 20 10:27:01 2024 daemon.notice netifd: wgclient (26547): sh: 1: unknown operand
Tue Feb 20 10:27:01 2024 daemon.notice netifd: Interface 'wgclient' is now down
Tue Feb 20 10:27:01 2024 daemon.notice netifd: Interface 'wgclient' is setting up now
Tue Feb 20 10:27:01 2024 user.notice firewall: Reloading firewall due to ifdown of wgclient ()

In another post it is suggested it could be a FW issue but I have checked manually ports being used in the confiiguration it is reachable.

Anyother suggestion why I am seeing this error.

AFAIK, none of these messages are a true issue. Just log noise.

Can you connect to the WG server by using an different device?

@admon : Thanks for ur reply, I suspect the same that there are intermittent problem with the WG Server.