Proxy error while trying to login

I am getting this error :

Error: Form security failed. Please reload the form and check that your cookies are enabled. If you use a proxy server, you must configure Piwik to accept the proxy header that forwards the Host header. Also, check that your Referrer header is sent correctly.

all i have is xyz.com domain

hosted on two different web hostings with cloudflare enabled

pointed A record from server where its installed to to the ip of another hosting

i am unable to login and even unable to reset password.