sorry, but not really. 405 means that plugin is using a request type that’s most likely not permitted. there is more then just GET and POST as you probably know.
so you first want to find, what exact call this thing is trying to send my guess would be a DELETE which probably isn’t allowed for security reasons.
then you can search for the location it get’s stuck. could be the proxy, the backend, who knows…
this is not really hestia related but a configuration thing for webservers. could be you need a custom config to make this work… maybe you also want to think security implications coming with that.
I am not sure if it can really be considered a bug. guess the dev went the easy way for handling things by using uncommon methods (http DELETE requests) which might work on some system but on some not.
who knows if he can find another to do the same to achieve better compatibility