You are using the 1721 port for the CCITCPGW startup port and it is already used by another systems.
If you checked your different systems, one should already have the 1721 port.
There are two solutions to resolve this problem:
1. You can adjust the protocol statement (in your CCIPARM) to be:
and then cycled ENF/CCITCPGW.
2. You can apply RO54035 so you can specify PORT=7000 in your CCITCPGW procedure and use it instead of the 1721 default.
APAR #: RO54035
Product: CCIMVS Release: 14.1 Solution #: 11
Title: PORT= PARAMETER IN CCITCPGW AND CCISSLGW NOT HANDLED