Migration to Plesk 12.5 is failing with this error:
[ERROR] Failed to perform action: Set security policy on Windows nodes
Cause: expected string or buffer
That is a critical error, migration was stopped.
postfix is set as default mailserver and option
Send from the specified IP addresses is set in Plesk > Tools & Settings > Mail Server Settings .
Bug #PMT-2343 . Fixed in Plesk Migrator l.12.
Install the latest version of Plesk Migrator.