This is my first ever post. I hope you can help - I've been searching the web for days now.
I am having the problem that many of my emails from a simple local PHP mail() command are not being successfully received:
Remote host said: 550-Verification failed for <email@example.com>
550 Sender verify failed
When I run a SMTP test on MXToolbox, it says: Warning - Reverse DNS does not match SMTP Banner
I can verify that my host has set the reverse DNS and this is proven via a ptr lookup too.
The server situation - Plesk with qmail. Two IP address / two websites.
The second IP address (i.e. not the primary IP) is the one that I need to send emails from the website. I assume this may have something to do with it?
I have tried to set the TXT record of this domain to include ip4:IP-Address-of-first-ip.
I imagine, I'm missing something basic? I'm afraid my knowledge is fairly limited - hence being on here.
Any assistance would be very much appreciated.