Some Antivirus programs block access to ports known to be used by some applications to compromise your system. For example MacAfee has a rule called "Prevent IRC communication" that blocks access to ports 6666-6669. If this rule is enabled, and if M3 Business Engine environment uses any of these ports, either disable the rule or exclude the following processes from the rule:
On the M3 BE server: java.exe
On the administrative client: java.exe and Lifecycle Manager.exe.
For considerations regarding antivirus program installed on SQL Server, see M3 Business Engine and Microsoft SQL Server - Best Practices" (SQL Server BPG) on Xtreme Documentation Portal.