Take a look at the current mailbox quotas. CUC admin > Message Storage > Mailbox Quotas > Mailbox Quotas. This will show you when a warning is issued and when sending/receiving is prohibited. You can adjust the global quota setting here or you can adjust for an individual user by going to Users > find the user > Edit > Mailbox. From this screen you can change the mailbox quota setting to custom and modify the quotas.
User deleted/cleaned his voice mail box by deleting all the voice mails, and I have tried removing voice mail profile from phone line and reconfigured, but it is still the same.
Did the user empty deleted items as well? Depending on your aging policy, deleted messages may be retained for a period of time which would still contribute to the mailbox quota.
