Hello,
To start, please update your device to the latest RUT_2_R_00.07.04.1 firmware version, with Keep settings option disabled.
If the issue persists afterwards, would like you to attach a troubleshoot file to your question. Please, replicate the issue, then access router's WebUI, go to System -> Administration -> Troubleshoot section and download troubleshoot file from there. The logs in the file might provide more insight into the issue.
Attached files are private and visible only to Teltonika Moderators.
Best regards,