We are aware of an issue with Logitech's Harmony API and Authentication services that transpired over the weekend of May 5th through the 7th.
One of partner services Logitech's API depends on suffered an outage in multiple regions, and as a result connecting to your Logitech Harmony account from Yonomi, or using your Harmony Hub via Yonomi, may not have worked.
We believe this issue is now resolved and things should be working correctly again. Logitech has informed us that although it is resolved, it may take several more hours for users in some regions to see functionality restored -- so please try again in a hours if you are still having problems.
You can see more information about this issue on Logitech's support forums here: https://community.logitech.com/s/question/0D55A00007Vv0XESAZ/harmony-hubbased-remotes-service-interruption-and-lag