Adding on that this broke after I recently updated the plugin identically to the above 2 posts.
I first tried unraid-api restart, as well as manual stop -> wait -> start. Uninstalled the plugin and reinstalled.
Uninstalled, made sure the config was blank and default, reinstalled and sign-in is still grayed out with unraid-api is offline error. Worked fine until the last update for me.
Unraid-api status claims it is online, but the the logs show the same as above 2 posts:
{"errors":[{"error":{"name":"InternalError","message":"Graphql is offline."}}]}