First, try to check the prerequisites :
https://learn.microsoft.com/en-us/azure/data-factory/connector-db2?tabs=data-factory#prerequisites
And the supported versions:
Specifically, this DB2 connector supports the following IBM DB2 platforms and versions with Distributed Relational Database Architecture (DRDA) SQL Access Manager (SQLAM) version 9, 10 and 11. It utilizes the DDM/DRDA protocol.
- IBM DB2 for z/OS 12.1
- IBM DB2 for z/OS 11.1
- IBM DB2 for z/OS 10.1
- IBM DB2 for i 7.3
- IBM DB2 for i 7.2
- IBM DB2 for i 7.1
- IBM DB2 for LUW 11
- IBM DB2 for LUW 10.5
- IBM DB2 for LUW 10.1
You need to configure the Informix Server to be “DRDA enabled”, and to listen for in-bound client TCP/IP network connections on a “DRDA port” (default port number is 9089). Here is a similar thread for your reference.
More links : https://learn.microsoft.com/en-us/answers/questions/1281170/adf-connecting-to-ibm-db2-cloud
https://community.fabric.microsoft.com/t5/Desktop/Connecting-to-Informix/td-p/122729