OK, if you got a server log like "SSH_FXP_STATUS: Maximum quota exceeded.Transfer aborted.", it indicates you have enabled the "disk quota" for a local user, if you use LDAP authentication, then LDAP user probably maps to the local user.
The issue has popped up again. Originally, the LDAP account is not mapped to local. I tried to add a local and map it and made sure no quotas are enforced on the Local account, and it has the issue still.