Unable to deploy AppCenter2.ipa to Mobile First Application Center - ibm-mobilefirst

Question

Following https://developer.ibm.com/mobilefirstplatform/documentation/getting-started-7-0/moving-production/distributing-mobile-applications-application-center/
When we build the IBMAppCenter project in MobileFirst Studio (v7) then Xcode (6), uploading the resulting AppCenter2.ipa file results in a simple red "X" and the message "File AppCenter2.ipa not uploaded".
The MobileFirst Server error log has no errors or any messages at all when this occurs, so we can find no details on what the failure might have been.
Note that we had to build the ipa file with xcodebuild as it seems Xcode 6 no longer allows us to do so from the IDE.
Also note that in Studio, instead of "Run As > Build and Deploy", which wasn't in the menu exactly, our developer eventually chose "Run As > Xcode", which seemed to be the only option that produced a non-trivial result. (I'll update with exact wording when I'm able to clarify with him. I don't have Studio installed myself.)
[5/8/15 13:16:12:425 CDT] 000000e3 WebContainer E com.ibm.ws.webcontainer.internal.WebContainer handleRequest SRVE0255E: A WebGroup/Virtual Host to handle / has not been defined.
[5/8/15 13:16:13:200 CDT] 000000b0 TaskThread 3 com.worklight.core.tasks.TaskThread trigger Triggered task ssoExpiredLoginContextsCleanupTask
[5/8/15 13:16:13:204 CDT] 000000df RssBrokerUtil 3 com.worklight.core.util.RssBrokerUtils beginTransaction Transaction begin : -1657954268 (new:true; completed:false; rollbackOnly:false)REQUIRED
[5/8/15 13:16:13:211 CDT] 000000df RssBrokerUtil 3 com.worklight.core.util.RssBrokerUtils commitTransaction Transaction commit: -1657954268 (new:true; completed:false; rollbackOnly:false)
[5/8/15 13:16:15:519 CDT] 000000e3 PureMeapBaseU 1 JNDI Access to ibm.appcenter.bluemix.brokenuri => null
[5/8/15 13:16:15:522 CDT] 000000e3 PureMeapBaseU 2 Found property ibm.appcenter.services.endpoint=http://-ourserver-/applicationcenter in webapp context.
[5/8/15 13:16:15:522 CDT] 000000e3 PureMeapBaseU 1 JNDI Access to ibm.appcenter.services.endpoint => http://-ourserver-/applicationcenter
[5/8/15 13:16:15:975 CDT] 000000b0 TaskThread 3 com.worklight.core.tasks.TaskThread trigger Triggered task com.worklight.core.clustering.ClusterSynchronizationTask#4fba3376
[5/8/15 13:16:16:017 CDT] 000000b3 RssBrokerUtil 3 com.worklight.core.util.RssBrokerUtils beginTransaction Transaction begin : 499307077 (new:true; completed:false; rollbackOnly:false)REQUIRED
[5/8/15 13:16:16:046 CDT] 000000b3 ClusterSynchr 3 com.worklight.core.clustering.ClusterSynchronizationTask getStackTrace mark singleton as hosted ssoExpiredLoginContextsCleanupTask
[5/8/15 13:16:16:047 CDT] 000000b3 ClusterSynchr 3 com.worklight.core.clustering.ClusterSynchronizationTask getStackTrace mark singleton as hosted PlatformUsageProcessingTask
[5/8/15 13:16:16:047 CDT] 000000b3 ClusterSynchr 3 com.worklight.core.clustering.ClusterSynchronizationTask getStackTrace mark singleton as hosted notificationCleanupTask
[5/8/15 13:16:16:048 CDT] 000000b3 RssBrokerUtil 3 com.worklight.core.util.RssBrokerUtils commitTransaction Transaction commit: 499307077 (new:true; completed:false; rollbackOnly:false)
(Some of that, like the SRVE0255E, is happening repeatedly independent of this application upload attempt.)
Update 2: Also couldn't delete another application that was already installed, nor overwrite it with a new one. Same UI error with nothing logged. Uninstalled Application Center enterprise apps and reinstalled them, and now can't install any apps. Again, still with no errors logged at all.

Answer 1

As suggested by Georg Sander in the comments:
Please contact IBM support to submit the full log file! If the trace
specification is set as above and you see absolutely nothing in the
log file, then some firewall blocks the access to App Center and it is
not reached at all. If it is reached, then for sure you have messages
in the log file about App Center.
It seems that this question is going nowhere and will require deeper investigation. Please open a PMR (support ticket) so that the development team will be able to help you, either by receiving your logs or by having a remote session with you to debug this issue.
There appears to be no feasible workaround to provide.