Certificate validation failed on V3

Sonarr version (exact version): 3.0.3.690
Mono version (if Sonarr is not running on Windows): 5.12.0.223
OS: Yosemite (running on a Hackintosh I don’t want to upgrade)
Debug logs: https://pastebin.com/jzNDWFm2
Description of issue:
So I decided to jump in and upgrade to V3 finally, and the install went fine, and Sonarr launched ok, but in the System Status I’m getting a “All indexers are unavailable due to failures,” but I wasn’t getting that with V2 (V2 was running fine before I upgraded).

When I checked the logs I saw the “Certificate validation failed” error, and then came to the forum and searched around, finding one article about it, which linked to other articles, but after reading through all those I wasn’t able to determine what to do to fix the issue (I have limited knowledge of Mono and whatnot so couldn’t figure out the steps).

Any help would be appreciated to get back up and running…thanks!

Ok I disabled Certificate Validation in Sonarr General settings for now and it seems to work, but I’m assuming I shouldn’t keep running it like that?

Disabled is the same as v2, ideally you’d fix the underlying issues with mono + macOS that prevents the certificates from validating, but that may not be possible with Yosemite.

I’ve been trying to read through different posts but don’t see a step-by-step on how to resolve it.

My question: is it worth spending a bunch of time trying to resolve it? What does certificate validation do?

Unless someone has the exact same issue you’re not likely to see a step by step guide, the unique combination of a rather ancient OS version and an older mono version is going to limit who has the same issue. Typically mono 5.20 (not 5.2) is recommended.

https://www.mono-project.com/docs/about-mono/releases/4.8.0/#tls-12-support this is the note from mono on BTLS support in mono 4.8 (when it was opt-in), the cert sync information may still be valid.

It verifies that the certificate from the server matches and is valid (signed by a real authority, hasn’t expired, is for the correct domain, etc), the same thing a browser does.