Hi,

We are in process to migrate all servers from an old datacenter to new datacenter. We have a Lync 2010 pool in old DC and now have built another pool in same organization in new DC. Both pools have SSL certificate from different external vendors. Old pool all servers have certificate from Comodo while new pool have it from Geotrust. We started moving few pilot users from old pool to new pool. While most of them are fine but few users are complaining that now they are unable to join any meetings which were created after they moved to new pool. Also if they send any meeting invite to others, then other also unable to join that meeting. Users are getting "Service Unavailable, HTTP Error 503. The service is unavailable". Since the issue is with few users only and not with all so we can say that Simple urls are published with no issues. I don't find anything in UCCP logs. Please help. Thanks.

• Edited by SaurabhMG Tuesday, June 23, 2015 3:59 PM spelling mistake

Hi, I rectified this issue by reinstalling web services on all FE servers. Also checked that in IIS .net 4.0 was selected for Lync while it should be .net 2.0 for Lync 2010.

• Edited by SaurabhMG 16 hours 27 minutes ago n
• Proposed as answer by Anthony CaragolMVP 14 hours 55 minutes ago