Mail transfer to Exchange failed, reason: Could not reach Exchange SMTP server - check IP port 25 is not blocked

This error message means that the Exchange SMTP service is not reachable from POPcon. Please check these possible solutions:

1. Is the IP address that POPcon finds for the Exchange server correct? Check the POPcon log file (C:\Program Files(x86)\POPcon\POPconSrv.log – open with notepad): You’ll find the IP address in [] after the server name in the log line just above the line with the error message. If it is not correct then this is due to a DNS problem in your server. Solution then: Just use the IP address directly in the POPcon configuration on the EXCHANGE tab instead of the exchange server name.
2. Check the configuration of the Exchange receive connector: Under SERVERconfiguration > hub transport > receive connectors > properties of the (default) receive connector > Network tab: Please check that your own server IP is inside one of the allowed IP address ranges under “remote addresses”. If not just add it.
3. Check that the “Microsoft Exchange Transport” service is actually running in the control panel > services applet.