Error 521 to specific links

Hello,

Time by time i am getting error 521 for random css and js files.

For instance https://example.com/assets/main.css may lead to error 521 but https://example.com/assets/main.css?2 loads just fine.

All seems to work fine after switching on the development mode from cloudflare->catching.

I am using plesk Obsidian on AWS server, and my domain has letsencrypt ssl certificate.

I run this issue with plesk support and they confirmed that there are no local issues on the server.

I really hope that somebody from here will be able to help.

Hmm, sounds like rate limiting, is this still an issue? Some 521 ideas here, Community Tip - Fixing Error 521: Web server is down