I'm having no trouble with other users. When testing through Telnet I get this message: "unexpected addiction characters at the end of command" The user has no special characters in his password. I've changed the password to something simple with no change in results. Any help would be appreciated.

Hi, I suggest using the steps below to troubleshoot the issue. 1. Open Exchange system manager, expand Admin GroupsServer--<Your server name>--protocolsIMAP4, choose Default IMAP4 Virtual Server and select properties. 2. In the Access table, check connection controls. 3. Check if this specific user is blocked. If it isnt there, lets move on. 1. Open AD users and computers 2. Find the specific user in User container. 3. Open the users properties, choose Exchange feature. 4. Double clock IMAP4, see if use protocol defaults has been checked. However, if the issue persists, please let me know what mail client you are using and let me know if you have enable SSL for IMAP4 connection. How to check if you have enabled SSL connection ============= 1. Open Exchange system manager, expand Admin GroupsServer--<Your server name>--protocolsIMAP4, choose Default IMAP4 Virtual Server and select properties. 2. In Access control table, click authentication. 3. See if require SSL is checked. Hope this helps. Thanks, Elvis

Thanks for all of that. I've been through each of the above steps and the problem persists. As for your last question: SSL is not enabled. The clients being used are Apple iPhones, but I've also tested the accounts using Microsoft Outlook. I created a brand new account and was able to use Microsoft Outlook, using IMAP, to connect to the mail server. Using the exact same settings (except username and password, of course), I could not authenticate with the account in question. I also tested an existing account with no problems. Thanks for your help.

Hi, First, I would like to confirm if the user name contains any of the following characters: [/\\""\[\]:<>\+=;,@] Meanwhile, please let me know if this account works well before. Did this issue happen after some configuration changes? Or this is a new account, it never works since created. I suggest using Outlook Express which only support imap4 or pop3 access to test this issue. Please click send/receive to see the detail error message and paste it here. I await your reply. Thanks, Elvis