Secure Connection Failed (Solved)

[Ageless]

When trying to log in on my account page at The Elder Scrolls Online I am these days met by the following outburst:

Secure Connection Failed

An error occurred during a connection to account.elderscrollsonline.com. Cannot communicate securely with peer: no common encryption algorithm(s). (Error code: ssl_error_no_cypher_overlap)

- The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.

I have notified the ESO developers and they say:

We have had some customers run into trouble with login and processing on our website when attempted from a Windows 10 browser. The website was configured with optimization for the browsers available at the time, so any new OS or beta browsers can have have issues with logging into our account.

Please try switching to another browser and continuing with the same steps again.

Problem is, I don't use Windows 10 (will stay far away from it, I'd like total control over my machine). I wouldn't say PM is a beta browser either.
Yet testing with Firefox 38 and 39, the page works fine. So then it would seem to be a PM problem.

It gives the same error if I try to change its URL to HTTP, from HTTPS. And it used to work in the past.
Toggling general.useragent.compatMode.firefox to true doesn't work either.

So, really something that ESO's developers broke and should fix? Or are there things I can try?

[Moonchild]

I hate to have to correct them but it is their server that needs to be updated. They are offering a single encryption cipher only, and it's one that has been disabled in Pale Moon (and will be disabled in mainstream browsers as well sooner rather than later).

See: https://www.ssllabs.com/ssltest/analyze.html?d=account.elderscrollsonline.com
Under "configuration" there's only a single cipher listed and it's RC4.
See the FAQ on this forum, top entry, for a workaround - but it's a temporary measure at best. ESO needs to properly configure their secure server.

[LimboSlam]

This is caused by disabling the RC4 encryption ciphers for secure connections in Pale Moon v25.3 and up. Please read this : https://forum.palemoon.org/viewtopic.php?f=24&t=6262

[Ageless]

Thank you Moonchild, forwarded that to their developers. Also put the recommendation from https://en.wikipedia.org/wiki/RC4 in it.
I will not try to work around this then using PM, and instead if I need to use Firefox.

[Moonchild]

You may also want to point them to the standards track RFC7465 at https://tools.ietf.org/html/rfc7465 - it's not just a "recommendation", it's actually strongly urged to phase RC4 out ASAP, and servers and clients, for RFC compliance, MUST NOT negotiate RC4 anymore.