While sending outbound emails from Pega, Gmail ids are considered as invalid. We have an exception in the OOTB Send activity. This was working fine for 8.4, but post upgrade to 8.8, we see a fix corr assignment getting added and the email is not getting sent. Outbound emails work fine for email ids within the organization.
Can you please share the stack trace from the logs when the outbound gmail id’s are failing. We may get some additional information from there to detect the actual root cause.