All indexers are unavailable due to failures : sonarr

Sonarr version
Mono version
Windows Home Server 2011:
Description of issue: Pretty much every day sonarr displays the error All indexers are unavailable due to failures for all 3 of my indexers.

The way to resolve is to restart sonarr and then individually test each indexer. I see that this issue has been an ongoing one going back manty years, but I haven’t as yet found a fix that works looking through previous posts. This is a brand new installation of sonarr and the error has been there form tsh start.

Any thoughts?

It all depends on your indexers, really. Sonarr v3 (probably v2 as well) has an increasing window where it will re-test indexers if they fail to respond, which caps at once every 24 hours if I’m not mistaken.
So the first time an indexer fails, sonarr will try again in… 5 minutes? then 10, an hour, two hours, … (making up numbers, but that’s the basis of it).

However, if this happens all the time and the indexers are fine, something else may be going on, and smarter people than me need to take a look at your debug logs.

This does not compute for me. OS is Windows, but you’re using mono? Perhaps in a docker?