user inability to assess their mailbox
Bilray, please provide more details about your problem.
At least, you should add a detailed explanation of the situation, and the Exchange and Outlook versions being used.
Yes, and please tell us what you mean exactly by “inability to access their mailbox”. Is this a new account or an account that was working and now is not? What troubleshooting have you performed? Are they getting errors? And if so please give those in detail. The more information you provide the more likely you will be to get a helpful answer. Thanks!
Is the user unable to access it using Outlook? OWA? Both of those? If you include those types of details, along with error messages and what software versions you are working with (i.e. Exchange 5.5? 2000? Outlook 2000? 2003? 2007?) as Carlosdl has mentioned, it would be much easier to get assistance. If you list the troubleshooting steps that Technochic mentions, it will prevent people from wasting time suggesting steps you have already taken – and also give people a chance to see where something may have broken down.