on another phone after few event create/delete the same error:

Mar 11 15:59:11 sogod [24470]: <0x0x7f37c2dba9d0[SOGoCache]> Cache cleanup interval set every 300.000000 seconds
Mar 11 15:59:11 sogod [24470]: <0x0x7f37c2dba9d0[SOGoCache]> Using host(s) 'localhost' as server(s)
2014-03-11 15:59:11.610 sogod[24470] -[WEClientCapabilities initWithRequest:]: Unknown WebClient: user-agent='Android/4.2.2-EAS-1.3'
2014-03-11 15:59:11.612 sogod[24470] Note(SoObject): SoDebugKeyLookup is enabled!
2014-03-11 15:59:11.613 sogod[24470] Note(SoObject): SoDebugBaseURL is enabled!
2014-03-11 15:59:11.613 sogod[24470] Note(SoObject): relative base URLs are enabled.
Mar 11 15:59:11 sogod [24470]: [WARN] <0x0x7f37c2e46c80[SOGoWebDAVAclManager]> entry '{DAV:}write' already exists in DAV permissions table
Mar 11 15:59:11 sogod [24470]: [WARN] <0x0x7f37c2e46c80[SOGoWebDAVAclManager]> entry '{DAV:}write-properties' already exists in DAV permissions table
Mar 11 15:59:11 sogod [24470]: [WARN] <0x0x7f37c2e46c80[SOGoWebDAVAclManager]> entry '{DAV:}write-content' already exists in DAV permissions table
EXCEPTION: <NSException: 0x7f37c2f3c090> NAME:NSInvalidArgumentException REASON:SoHTTPException(instance) does not recognize delete INFO:(null)
Mar 11 15:59:11 sogod [23889]: <0x0x7f37c2ba8df0[WOWatchDogChild]> child 24470 exited
Mar 11 15:59:11 sogod [23889]: <0x0x7f37c2ba8df0[WOWatchDogChild]> (terminated due to signal 6)

delete ActiveSync account on the phone resolves issue

So you get the error when you try to delete an event from the phone?

No, scenario is:

• connect mobile phone with ActiveSync - sync working
• create event on webpage - sync working
• delete event on phone - sync working
• create event on phone - sync no longer working

I'm not fully sure how can this happen but I've added a safety check to prevent it.

https://github.com/inverse-inc/sogo/commit/1bdf88fb67f89361978e601da6c5ed74b3042f27