Outlook client suddenly disconnected from exchange

Try creating a new mail profile from Control Panel > Mail. Do not try and modify the existing profile as it sounds like it was set up for Offline use.

Also, instead of using the Exchange server name, use a Domain controller name or IP address. If this fails, there's an underlying problem in this user's access to Global Catalog port 2468 on the DC.

Has there been any changes to the user's AD account like Group Policies?

" when i remove the exchange account from the mail settings on this client, then try to re-add them, when i Check Names, it says the exchange server is unavailable."

-i am creating a new profile.

i can also add this user's exchange account to Outlook on a different PC and everything works fine.

i made this user a domain admin yesterday. that is the only change to his AD account.

What happens when you substitute a DC/GC in the Exchange server box for Mailbox name resolution during mail profile creation?

the same thing; the name cannot be resolved. but when i log on to the problem machine with my roaming profile, outlook still doesn't work. i tried to log onto MY machine with the problem user's roaming profile to prove a point, but he has a 2.5 gig profile and i can't load it for whatever reason. but i can log on to my machine with a third,  dummy profile and create the problem exchange account in outlook, and everything connects fine.

wow. i have deleted the users AD account, exchange account, then re-created them, then disjoined his laptop from the domain and rejoined it. still it will not connect to the exchange server. all other network stuff (mapped drives, etc.) work fine. is that port you mentioned the one that exchange communicates on? how can i tell if somehow this got blocked?

i also created a new outlook profile (sorry, i misread your first response), but when i try to add the exchange account i get the "the action could not be completed. the connection to the microsoft exchange server is unavailable. outlook must be online or connected to complete this action."

This part right here "outlook must be online or connected to complete this action." means the profile is configured for Offline use. Create a new mail profile and make sure this is not enabled. See if there's a different error or if it works.  Offline can only be enabled *after* there's a successful connection and you are actively logged into the mailbox.

fyi, uninstalling TCP/IP and reinstalling it fixed the issue.

I am experiencing this exact problem, unfortunately none of the above solutions have helped my cause.  We have recently purchased a new Dell 2400 Dimension with XP Professional.  We can connect to the Exchange server (2000) and setup the account without any problems.  We can also send email and view the Global Address List after the initial configuration, if we close the Outlook client and reopen it, it says that the server cannot be located.  If I go to services, I can remove the account and readd it without any problems, but I still cannot reach the GAL or send email.

FYI: We have reinstalled XP on this unit on 3 occasions.  We also have a second unit that is identical and did not have any problems with it. To make it more complicated, we have loaded 3 more 2000 Professional machines on the network this week and have not experienced any problems with them either.

Any ideas?

first of all, open up a new question and award some points. post a link to the question here.

all other net functionality is ok on this unit? internet, logging onto the domain, shared drives, etc? can you ping the exchange server from the problem machine? DNS is set up ok? what version of outlook? can you connect to the server with pop3, imap, and OWA?

https://www.experts-exchange.com/questions/20912931/Outlook-problems-with-Exchange-2000.html

Thanks removing tcpip and reinstalling fixed my problem saved hours of work reinstalling everything
Thanks mark

Try deleting some mails from the mailbox via outlook web access. delete sent itemjs and deleted items. Worked for me!!

I had problems with users using Outlook 2007 getting stuck in a Disconnected state, and it was linked to Cached Exchange mode too. Not sure if your problem is the same thing, but try disabling the "Download shared folders" that is enabled by default when you use Cached Exchange mode. I have a post on my blog about it here: http://techierambles.blogspot.com/2008/09/outlook-2007-stuck-disconnected.html. It seems that Exchange has a 32 session MAPI limit, and for some reason Outlook 2007 will exceed that limit and have problems connecting to the server. I think the default lockout is 2 hours. If you want to double-check it, check your Exchange server event log for event ID 9646, or look at http://support.microsoft.com/kb/842022 for more info. You can change the MAPI limit on the Exchange server if you want, but if it's only a small number of users you may just want to uncheck that one setting. Good luck!

How do you actually uninstall/re-install TCP/IP?

When I look at the properties of my network adapter and select tcp/ip the unistall button is grayed out.

www.rubberducktech.com

Note: Regarding the 32 sessions exceeded situation, most often this is due to a Search toolbar such as Google scanning the mailbox multiple times during a connection so the sessions pile up. The only ways to clear the connections is to A) move the mailbox or B) wait for them to clear (not guaranteed to happen). Check the user's machine for IE toolbars and the like.

I wonder if Explorer 8 has something to do with it ... I started getting these issues after the update !!??

The user account was locked out in AD.  I unlocked the account and restarted Outlook.