It’s About Time

My latest joy was tracking down a Lync problem where users on just a single pool were seeing the “Limited External Calling” error in their client after signing in. This had been working previously and no changes to the firewalls, certificates, DNS, or servers had taken place. All the usual stuff checked out OK and the logging traces on the client actually looked pretty clean. We saw no errors on the server and all other functionality seemed just fine.

After digging through the server-side traces I finally noticed a few diagnostic messages appearing periodically while looking for MRAS issues (some portions snipped for readability):

LogType: diagnostic
Severity: error
Text: Message expired in the outbound queue before it could be sent
SIP-Start-Line: SERVICE sip:<Edge Internal Pool Name>:5062;grid SIP/2.0
Peer: <Edge Internal Pool Name>:5062

LogType: diagnostic
Severity: warning
Text: Message or one of its headers caused SIP transaction processing error
Data: Transaction Time-out: Type [2] Method [0x40] Call-Id [7d8d76435a474b568f430436e49cfcfd\n] RUri[sip:<SIP URI>;opaque=user:epid:uZWEVFe3nFqIKFtM_NzmFwAA;gruu] From[<SIP URI>;tag=8E780080] To[<SIP URI>;tag=af1b73d16f]

The timeout and expiry messages finally clued me in on the real problem – it turned out the timezone on this server had been flipped incorrectly by an automated process.

After correcting the clock settings and restarting the FE services we found the A/V authentication working properly again. So if everything else looks correct, it may come down to the basics – make sure your clock is set properly.


Recent content I've written for you—just for you!— to enjoy while you're here.


Quick commentary and links to other sources you'll find interesting. I promise.


Some personal background, links to related projects, and other ways to connect.

Hi there. My name is Tom Pacyk and this is my small home on the web. I love the intersection of design, technology, and communication, which is a combination that led me to a career in sales and marketing roles at places like Zoom and ServiceNow. They're a bit old now, but I also had the opportunity to publish a couple of books along the way.

Portland, Oregon is home for me, my wife Beth, and our three kids, but I'm actually a Midwestern transplant—I grew up in the Chicago suburbs and went to school at Purdue and Illinois. When I find some free time I'm probably going to concerts, rooting for the Portland Timbers, or working on my Sunshine Burn Photography project.