Reported error:
550 5.0.350 Remote server returned an error -> 553 Message filtered. Refer to the Troubleshooting page at;http://www.symanteccloud.com/troubleshooting for more;information. (#5.7.1)
DSN generated by:
VI1P122MB0079.EURP122.PROD.OUTLOOK.COM
Remote server:
server-15.tower-381.messagelabs.com
Submit a sample of the email that's blocked to:
investigation@review.symantec.com
reference links:
https://www.symantec.com/docs/TECH82881
https://www.symantec.com/docs/TECH250089
https://www.symantec.com/docs/TECH240145