Customer stated as of yesterday, when ringing through the auto attendant and dialing 0 they receive a message "that extension is not valid". I verified this is true. I, at that point verified that while onsite, I can pick up a phone and dial 0 without going through the auto attendant and it does work.
Voicemail is an Express Messenger.
Any help would be appreciated.

I believe you have to program a mailbox for the operator's extension.

I think someone entered vm programming and changed the extension. You can verify with the mem software or via the admin box.

Yes, the mailbox 0 was changed to 9404xxxxxxx, I deleted and input a 0, tested fine. The funny thing now, is I cannot change the passord to mailbox 9999? It denies me? NOW WHAT! If it aint one thing its another?

Were the passwords default? Sounds like someone was highjacking VM for outbound calls. If you aren't doing external notification I would block the voicemail from accessing external lines.

Jon, thank you for the suggestion, I did have the VM ports denied, you never know when you will overlook something so small. My probem still is I am unable to change the Administrator password under mailbox 9999. I enter administrator mailbox, press 6 to change the password, then 1 to change it, and it says "Invalid selection".
It is default, and I must get it changed, any and all help will be appreciated.

Try logging into the "Tech" mailbox and changing the admin passcode from there.

I went to the site, listed out all mailboxes, I did not see a "Tech Mailbox". I am not a master of any systems, but am able to work on a bunch of them, so your help, as always, is greatly appreciated on assisting me on resteeing the password on mailbox 9999....

When you log into mailbox 9999 there is a Tech/Installer passcode and there is an Administrators passcode and it depends on which code you use as to what options you have access to.

I attempted the *9999 and the passcode that "Telephoneguy" PM'd me, and that passcode does not work. I battle life everyday, LOL.
Any other ideas?

Still looking for an answer guys.... :bang:

If the default admin password has been changed and you can't get in, there aren't many options.

You could contact Mitel and see if they can get into it and reset the password. You could buy a hard drive with the express messenger software on it and swap the disc and reprogram. I'm not sure which file on the disc contains the password, but maybe someone knows and can get you the default file.

What version of software is the Express Messenger running. If it is an old version the passwords were different.

Silly questions:
1. Are you deinitely using 4 digit mailbox numbers? So, the admin box is definitely 9999?
There is a system option that sets length of passwords.
If it's NOT 4, you have to preface the default admin password with 0's, so you have the proper number of digits in your password length.