Sometimes a script can cause this. It means that you (well, your browser ofc) are trying to access the WK API more often than what they allow per minute. If you open the console, you might see a lot of accesses to WK and maybe you can identify the culprit that way…
I saw this a lot with the WK External Definition script; I adapted the original script and fixed these issues, so maybe this helps for you as well? You can find the new version here: