Hello,
I'm sorry to hear that you're having issues!
Are you using the SIM cards in slot 1 and slot 2? Or are you testing them by putting both of them into the SIM1 slot?
If they are both inserted into the router at the same time, SIM Switch would need to be set up in order for them to switch between each other.
Auto APN could also be causing issues here.
To troubleshoot the issues further, I'll ask you to attach a troubleshooting file. It can be generated by navigating to System → Administration → Troubleshoot. Please replicate the issue beforehand.
The file can be attached to the original query. It will only be visible to Teltonika moderators.
Best regards,
DaumantasG