What to do when you get a “504 (Server time-out) response” for Lync mobile push notifications?

February 16th, 2012 | Tags:

TechNet forums, blogs and tech news sites are ablaze with plenty of Lync Mobility related tips and news. Even I’m a UC Blog has seen a daily increase in traffic (circa 150-250 visits) primarily targeting mobile related content. So I thought it would be useful to pull together some potential solutions on how to address common push notification issues.

First off lets cover some basics:

  • Push notifications are only available for Windows Phone 7 and iOS-based devices (iPad/iPhone).
  • Push notifications are sent via Microsoft’s Lync Push Notification Clearing House or PNCH. (see diagram below)
  • To send push notifications via PNCH you will need a Lync Edge Server that has dynamic federation with Office 365 or push.lync.com. Setup instructions are available here

Now some common problems and solutions/workarounds:

  • URL Filtering Policy – at this time URL filtering blocks push notifications, until further notice from Microsoft a workaround has been published here
  • Missing SRV record – an SRV record must be configured for the Edge Server that initiates the outbound connection to push.lync.com. For more information check out this article from fellow MVP Randy Whintle.
  • Sub-domains - for organisations that have a SIP domain and Federation record mismatch. For more information check out this article from fellow MVP Kevin Peters.
  • Connectivity – ensure port 5061 is open (this will already be open if you have an already established Edge Server).
  • Default SIP domain is incorrectly specified – To display existing domains type “get-csSIPDomain” within the Lync Management Shell, to correct this type “set-csSIPDomain <SIP.FQDN> -isDefault $true”
  • Public Certificate – for any kind of federation to work certificates need to be provisioned via an external certificate authority. For more on approved certificate authorities, read this TechNet article.

If you can think of anything I have missed off, let me know and I’ll add it!