We have added cloudflare CDN before our server by changing the NS record at domainlevel and added same DNS record (NS1 and 2 along with all MX, A, CNAME, TXT) with cloudflare.

Website is working fine, but emails are failing from IPS backend.

Is there any new setting needed at the IPS backend too? Please help.

When I try to resend a failed email, we get this error message.

Edited December 13, 20231 yr by Gauravk

So we temporarily shifted to PHP emails

It looks like its simply being blocked. There is nothing on the IPS side of things that would cause what you are seeing there

Make sure your DNS settings for mail are not proxied, this way they are routed back to the origin server.