Well I’ve seen suggestions for the SMTP plugin, but the thing is that it works perfectly fine on website 1, so the server is clearly configured to handle phpmail. Also this form on website 2 DID work fine for months now, only recently it started getting this error. I checked the server’s stack and they haven’t changed anything on me. I’d rather not get additional plugins, especially since phpmail works and this site is bloated enough as it is. Also the website and mail both have the same top level domain.