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I have several computers... only one of which cannot authenticate to either my exchange or TFS server. (2 of the computers are at my home trying to connect to our exchange/tfs server at work, one of which as the problem). Several other employees have not had any connectivity problems.

The errors I am seeing are

401 2 2148074254
401 1 0
401 1 2148074252

After about 2 days of hunting around, I am about ready to repave the computer and start from scratch. As far as I can tell they are set the same.

I cannot connect to Exchange OWA using Firefox but not IE. Same for TFS. I have reset IE (using the tool at this URL: -- if you have not seen it you should read the description, it is quite entertaining). I have compared the trusted site settings between the one that works and the one that doesnt. I have also compared the 'advanced' settings and can find no differences. The credentials work perfectly from the 2nd computer, which eliminates any firewall related filtering problems.

I am at a total loss as to what else to try. Does anyone have any ideas?

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That's a great KB article. – Ward Jul 19 '09 at 7:35

wild guess here, but is there a time skew? depending on the AD settings your clock may only be a few minutes out before this is a problem

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I verified that the time is in sync, I can remote desktop back and forth as well. It is just exchange and TFS that appear to be having the problem. – john bergman Jul 20 '09 at 5:41

Given the specifics of your setup it seems unlikely to be the cause but I have seen problems exactly like this with network load balancers and nic teaming. Your description seems to rule this out as there are many systems working and only one failing but if you have a load balancer in front of your OWA\TFS front ends then it might be worth checking that all possible routes are healthy. If both of your remote systems are behind the same NAT router then this is even more unlikely but if not then it might be worth swapping around the ip-addresses to see if the problem moves with the address, if so then I would strongly suspect that NLB\teaming issues are involved.

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All computers are behind the same firewall, there is no load balancing in play, nor do I have teaming nics. I brought the computer into work today, and it works slightly differently. I can connect to outlook web access now, however TFS still gives the same error. The error has been shown as 'TFS31003 your account does not have permissions to connect to the Team Foundation server'. This is totally not the case, it is the same credentials I use everywhere on the company network. This leads me to believe that there is still some subtle setting I am missing, or needs to be cleared. – john bergman Jul 19 '09 at 19:06

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