Whenever i try to sync zotero app with my account on zotero.org the app says that username or password are incorrect. Eventhough i can log into zotero.org without any problems
This almost always just means you're entering the username or password incorrectly. Clear the fields completely, restart Zotero for good measure, and then try again.
If you're still having trouble, provide a Debug ID for an attempt to set up syncing that fails. (Your password won't be logged.)
Upgrade Storage
If you're still having trouble, provide a Debug ID for an attempt to set up syncing that fails. (Your password won't be logged.)