Getting Error code 520

Hello, I’m proxying a WordPress domain via Cloudflare. and it’s running on PHP8.2
whenever I try to purge the wp-rocket cache I get this error from Cloudflare.
'Web server is returning an unknown error Error code 520'

When I check the logs I get this from nginx

*1048 open() "/home/test/web/" failed (13: Permission denied), client: 95.216.xx.xx, server:, request: "GET / HTTP/1.1", host: ""

when I turn off the Cloudflare proxy and try to purge the cache it works fine.
when I downgrade the PHP version to 7.4 and it is proxy via Cloudflare it works fine.

the issue only occurs when we upgrade the WordPress PHP version to 8.0-8.2 and it’s being proxied via cloudflare.