Hi,
Based on your situation, the network trace collection is necessary to analyze the issue deeply.
However, analysis of network trace is beyond our forum support level. So I would suggest you contact Microsoft Customer Support and Services where more in-depth investigation can be done so that you would get a more satisfying explanation and solution to this issue.
You may find phone number for your region accordingly from the link below:
https://support.microsoft.com/en-us/help/4051701/global-customer-service-phone-numbers
Hope my answer will help you.
---Please Accept as answer if the reply is helpful---
Best Regards,
Sunny