I tried two different Verizon USB modems: UML290 and 551L, and I cannot make any of them work with my GL-MT300N-Mango.
I’m using a Verizon SIM card (4G LTE service) that I previously tested in GL-MiFi (with the global modem module inside), and it works fine there with full 4G speeds.
The 551L actually connects, but only gives me 3G with very low speeds. The UML290 never connects, it just keep connecting and showing “Abort” button but never completes. The router recognizes both modem as Verizon and the APN is automatically set to VZWINTERNET, which I think is the correct one. I reset both modems but no change. Is there any other trick to make these work? If not, which USB modem can you recommend that is guaranteed to work with a Verizon 4G SIM?