I will ask you to generate a troubleshoot file from the device. On RMS, this can be done by selecting the device and in the Actions drop-down menu selecting the Export troubleshoot option. This file can be attached to the original question and will only be visible to Teltonika moderators.
From the information available now, I believe you have accidentally locked yourself out by entering the incorrect credentials, and the IP block service blocks the IP address.
One way you should be able to access the device is by generating the remote access link to the router itself. On RMS, navigate to RMS Connect → Remote access. Press the +Add button, and select the device in question. Select the IP address of the router (192.168.1.1 by default) and select the 80 or 443 port. Try accessing the link and check if the router is accessible.