Dear Amit,

you can check below links reply if it helps you.

Change list specified is already closed. Status: submitted(CL ALREADY CLOSE

Not able to delete communication channel ID

else go to Integration builder and  click on Administration check Lock Overview for Repository.

if you find any locks remove those.

you can also try for cache refresh.. give it try.

let us see if you get any better reply from others.

Regards,

Muniyappan.