Something has gone wrong in your environment, some process didn't start. This kind of error "Execution URI input line was not set." is also thrown when you are trying to execute WFA cmdlets from outside of WFA.
Now what went wrong, I have no idea at the moment. Looking to see what can we get.
Just to ensure, you have rebooted your WFA server box? Try if not done already.
If this post resolved your issue, help others by selecting ACCEPT AS SOLUTION or adding a KUDO.