@vishweshpatil can you check if your firewall allows connections to our online library repository?
You must be able to access https://library-repository.aimms.com in your browser
See Library Repository — AIMMS Documentation
Please note that when using these libraries on AIMMS PRO, it needs access to the AIMMS library repository (URL: https://library-repository.aimms.com/aimmslibs.all , port number: 443). You may check/adjust firewall settings on the AIMMS PRO server in the case when AIMMS PRO is not able to access the AIMMS Library Repository