Did this problem get solved? I got the same issue. Login at Zotero.com was successful, while failed for the desktop version using the same username and password.
(Please start new threads for new issues — there's no problem with logging in, and certainly not one that's gone unfixed since 2019. I've moved this to a new thread.)
You made too many login attempts with the wrong password and were temporarily locked out. Now that some time has gone by, try again with the correct password and it should work.
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You made too many login attempts with the wrong password and were temporarily locked out. Now that some time has gone by, try again with the correct password and it should work.