Service Unavailable - Message - Plugin Updates

[KloudstackHosting]

Issue Description:
Over the past couple of weeks, I’ve encountered the following error popup when updating a plugin. It appears to relate to a timeout, but the plugin does successfully update despite the error.

Observations:
The error code displayed in the screenshot does not appear anywhere within Application Insights or Azure Front Door logs.
The server application itself is running fine, with no other noticeable issues.

Question:
Has anyone come across this error displaying in a similar way? Any insights on identifying the root cause would be appreciated.

[samrueby]

I run about 10 websites on the WordPress container in Azure. They're all still using the Alpine image. I have not seen this message before.

That message appears to be coming from Front Door. Check to ensure your custom domains configured correctly.

[KloudstackHosting]

Hi @samrueby

Is there any reason you're still running the older image “wordpress-alpine-php”?

All sites we run are running on “wordpress-debian-php”

In regards to Front Door, most of the sites we run custom domain setup APEX(Root), www(RuleRedirect) & Staging OR Dev and in some cases, we may run the custom sub cdn URL for customers that do not have a DNS for CNAME flattening. And most will also run WAF, with custom rules.

Yes, all is configured correctly, generally, when you get this wrong it won't work at all.

Origin response timeout is one area I have been reviewing, with the FD default set to 240 seconds, some are set to 30-60 seconds.

Question are you running any sites in multiple instances eg 2 or 3 set to Manual as autoscaling is not great for WP?