I enter user/password and click on Submit. Nothing happens, so I click again and get "Your session has timed out. Please resubmit the form." So I do and then I get:

"Secure Connection Failed

An error occurred during a connection to www.lotro.com.

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."

This has been happening for 2 days now. I can log in with MS Edge (ugh) with no problem. Firefox is v92.0 (64 bit).