I'm also getting the same issue. I think it's due to the Handy servers. This was posted on the Handy tech support discord channel this morning:
"We are experiencing some load issues. We have pushed some fixes that should have solved the most critical errors that some of you have experienced. The API is still a little slow and has high latency in some cases. We are working on solving that now. The good thing is that we are experiencing these issues for the first time since there are so many Handys connected and using our services. Thank you for your patience and feedback"
Maybe try again later today when they resolve the issues.