When Easy2Sync for Files accesses other computers, it uses the Windows mechanisms for file and folder sharing. Depending on the Windows version and configuration the security is managed differently. It can happen that Windows asks for a password, but none of your passwords seems to work.
Solution: Enter the following:
All 3 pieces of information do not refer to the computer where the question appears, but to the *other* computer. Effectively the computer that needs to verify this information for security reasons.
Note 1: This is Microsoft's idea. Easy2Sync can't help it..
Note 2: This page is only about problems with Windows passwords. Not FTP passwords.
Tipp: You can store username + password in the task. Then Easy2Sync will manage this for you.