The number one suggestion of Invalidate Caches/Restart... did not work for me nor did any of the other solutions. It ended up being that my maven repos were incorrectly set up, I fixed this by manually overriding the settings.xml and repository directory:
File -> Settings... -> Build, Execution, Deployment -> Build Tools -> Maven
Then for User settings file and Local repository, check the Override and point it to the correct settings.xml and repository directory.