Secure Connection Failed - SSL_ERROR_RX_RECORD_TOO_LONG
Using the current version of Firefox (v81) this happens when connecting to the admin page of the VR2800 V1.1 (EU):
Secure Connection Failed
An error occurred during a connection to 192.168.1.1:8080. SSL received a record that exceeded the maximum permissible length.
Error code: SSL_ERROR_RX_RECORD_TOO_LONG
The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
Please contact the website owners to inform them of this problem.
I'm currently unable to login to router, and only have the limited functionality of the Tether app for mobile.