The robocall left a message that it was asking me to join a live streaming town hall event for Cory Gardner, Colorado politician, and leaving another number I could call to join the event by phone. Chalk it up to political survey type of call and it is not illegal in Colorado.

Robo call for a Cory Gardner telephone town hall

Robo call from Cory Gardner.  Reported as spam, there is no way I am on any of his lists

Automated call from Senator Cory Gardner

Phone townhall for Sen Gardner. One has to sign up to be called.