W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://apt.insynchq.com/ubuntu trusty InRelease: The following signatures were invalid: KEYEXPIRED 1473479811
I am on trusty, UM 14.04. I got the same error message. It started a few days ago. Now I don’t get this error message anymore. I guess they fixed the key somehow…