Problem Upload Unity-App in Enterprise

We have been experiencing some problems with the development of in-house applications this month. Applications that were created with XCode only, we can load and distribute on our MDM (using Zuludesk and others). Applications created with Unity cannot be uploaded anymore, although this was possible last month (december 2019). Undere Enterprise License is ok. The created IPA files (for Enterprise) can also be "moved" directly to individual devices with iTUnes (music). We need here urgent support or a hint how to upload these IPA files.