I see it says you can use email addresses or IDs. Is it failing on email addresses because one or more the email addresses is not in your tenancy?
If they all are and it's failing anyway (wouldn't surprise me to find a bug in PA) then you can do this:
1. Initialise an array variable.
2. Add a compose and put the expression split(triggerOutputs()?['body/ccRecipients'],';') in there
3. Add a Filter array action with its input being the output from step 2 and the advanced mode condition being @endswith(item(), 'mydomain.com') where mydomain.com is your internal domain name. This is to filter out external people who you can't start a group chat with
4. Add an Apply to each using the output of the Filter array action as its input
5. Inside the Apply to each add a Get User Profile (V2) action using the Current item from dynamic content (or items('Apply_to_each') as an expression if it's not there)
6. Still in the Apply to each, go Append to array variable and append the id dynamic content from the action above
7. After the Apply to each loop, add a Join action and join the array variable on a semicolon character
8. Use the output of the Join in your Teams action.
