If all connectors are in the SYNCING state but modifications are not being synchronized, then verify that the synchronization settings are correct.
Using the Identity Synchronization for Windows console, verify that modifications and creates are synchronized in the expected direction, for example, from Windows to the Directory Server. Also verify that the attribute being modified is a synchronized attribute. If created user entries are not being synchronized, then verify that user creation flow is enabled in the Identity Synchronization for Windows console.
Passwords are always synchronized.
If you are still experiencing the problem, check if the source connector detects the change to the user. Use the central audit log to determine if the connector for the directory source where the user was added or modified detects the modification. Also verify that the destination connector processes the modification.