Not ready. Please check your connection.

Hi,

TeamViewer working fine for a long timeand then suddenly the error message mentioned:

"Not ready. Please check your connection."

My internet connection is fine. Also, cant sign in. (Presumably part of the same problem.) "Sign In" button is greyed out even after entering my password.

This happened after I was invited to update, which I did. TeamViewer V. 12.0.139437, Mac OS 10.9.5

Anyone know what happened here, and how to fix it?