I had a browse for this issue on the forums and found many posts but no solutions.
We have a IIS server for staging using Lets Encrypt Certs.
This has been working fine until the past week or 2 when suddenly some sites started throwing the error “ERR_SSL_VERSION_OR_CIPHER_MISMATCH”
I noticed when loading the https site that it does not show a certificate so I disabled Universal certs, and 20 min or so later re-enabled them again but alas no change.
We use Full Encryption but not strict. The web server has TLS 1.0 & 1.1 disabled as per best practice, and CF set to accept TLS 1.2 as minimum so I assumed that allows the cyphers to work both ways same protocols.
I tried disabling TLS 1.3 from CF end and again no luck.
Site works fine without proxy, but I do not like exposing the server external, especially due to no trusting web developers with security.
Anyone have the slightest clue what the issue could be?
Just to note.
1 of the sites on same server using LetsEncrypt works fine.
Its throwing me off.