550 validating sender outlook

The error when limit reaches is "we do not relay, account limits apply".

So if you wanna be safe, do something like the image in this faq: https://suporte.icewarp.c...-ler-logs-do-anti-spam So: - Your connections per min is too low. because this blocks an IP in case of x failed attempts, so imagine, you can block an entire company if they use same OUT IP because of 1 user putting wrong pwd... Thats 1 of the main feature, it blocks dictionary attachs, if over x invalid receipients, block for x minutes and enable cross session and close connections. The idea with this feature is to avoid people sending HUGE files to yoru customers. ITs because SMTP (not ESMTP) has to receive entire message before knowing size.

So if your system is receiving (from out to IN) a msg over x megabytes, block user's IP.

I've also made sure that the ports are successfully aligned so as to not mess with the firewall.

The user can receive emails; she just can't send any. A “550 Access Denied – Invalid HELO name” SMTP error usually occurs when the SMTP Domain configured as part of an email sender’s identity does not match the senders email address.

In that case Icewarp would refuse email as it came from a local sender that did NOT auth via icewarp.