Migration from Microsoft Exchange 2010 to O365 fails with – ErrorInternalServerTransientError
Check and ensure that your server is up and running. If you are able to connect to your server from
the Internet, this error may have been caused by intermittent network or I/O problems.
By default in Exchange 2010 , sessions per user are limited to 32, and service sessions per user are limited to 16.
– On the server that is running the Exchange Server 2010 Mailbox role, Open Regedit
– Locate and then click the following key in the registry:
– Create a new DWORD – Value – Maximum Allowed Service Sessions Per User
– Type the decimal value that specifies the number of sessions that you want to use, click OK.
– Exit Registry Editor.
– Restart Information Store Service
Hope this will help
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