Server unable to set up secure connections: PKCS12_parse failed (FIXED)

[EnglishMossop]

Server Version: 1.32.0.6918
Player Version: Plex Web 4.100.1

Since I updated my server a day ago it is no longer usable from https://app.plex.tv/ as it appears to be unable to set up secure connections. The server is logging this hundreds of times:

Apr 11, 2023 09:25:47.664 [0x7f3abc497b38] Error — [CERT] PKCS12_parse failed: error:0308010C:digital envelope routines::unsupported
Apr 11, 2023 09:25:47.664 [0x7f3abc497b38] Error — [CERT] Found a certificate, but couldn't install it.
Apr 11, 2023 09:25:47.666 [0x7f3abc497b38] Error — [CERT] PKCS12_parse failed: error:0308010C:digital envelope routines::unsupported
Apr 11, 2023 09:25:47.666 [0x7f3abc497b38] Error — [CERT] CERT: Error acquiring new certificate: Failed to open temp file

I’ve seen the other forum posts about the changes impacting user-provided certificates but I am not using a user-provided certificate.

[EnglishMossop]

It is repeating this logging maybe hundreds of times per second and the media server process is consuming 120% CPU usage (it’s a multi-core machine). I’ve tried adding a user supplied certificate but the logging and CPU usage continue.

[EnglishMossop]

Looks like this was caused by a permissions problem with the Cache directory. Not sure why it only started causing issues with the latest update.