MDS0090E TN3270 listener port must have a valid value

When adding an MSS-enabled enterprise server region, a TN3270 listener is defined by default. This default listener has not had a port value defined for it, or the defined value is outside the standard TCP port value range.
Note: The port value must be greater than 0 and less than or equal to 65535. Certain port ranges have restrictions, depending on platform and version used. You should avoid port values already in use.