Wikipedia constant TLS errors

Question

This used to be an intermittent issue, but today it's showing up all day.

I sometimes get PR_END_OF_FILE_ERROR when trying to access Wikipedia trough Firefox. Refreshing usually does no good and I usually wait around a bit and the issue resolves itself. But today this isn't working.

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First, I tried switching profiles and following the advice on this answer but to no avail. Then I tried opening the site through multiple browsers and all of them showed errors

• Chrome: ERR_CONNECTION_CLOSED
• Edge: Can’t connect securely to this page
• Firefox: PR_END_OF_FILE_ERROR
• IE: INET_E_RESOURCE_NOT_FOUND

I've tried accessing the HTTP version, but it only serves a redirect. And finally, I've tried accessing it through a proxy, which worked but left me scratching my head for answers.

I thought about it a little and maybe it has something to do with my Windows certificate chains, but for what I gather online Firefox uses its own to do the TLS verification so I'm drawing blanks here.