Please check that you have the correct AVAYA CMS IP address configured in the Optymyse connector (login to the administration console, go to configuration - > connectors, choose the CMS connector and click Edit.) There is an option to restrict CMS to certain IP addresses, this either needs to be the correct IP address, or entirely absent.
Be aware that, if it is absent, then any network monitoring tools you may have (the type which search for vulnerabilities) may be able to make a connection to the port, which disrupts the connection with Avaya.
Assuming the IP is correct in the configuration, then there are no barriers to Avaya connecting within our software. You can use the "netstat -a" command in a command window to verify whether Avaya is connecting or not.