Hi Pietro,
I have checked the IP against the .cloud Blacklist again and can still confirm that these are not listed with us and we would not be blocking your emails for this reason.
We will not be blocking your connections when sending emails from any of those IPs to our .cloud customers.
Should you still have issues sending to Symantec customers, it may be part of the Messaging gateway products to which the .cloud team have no access to. If you do have problems with them, you will need to raise this in their Forum:
https://www.symantec.com/connect/security/forums/messaging-gateway
Please set this thread as resolved to ensure others do not add to it.
Kind regards
Kevin Brosnan
Tier 2 Senior technical support engineer