Migrate a TM to the cloud fails, due to an error in a "POST" command(?)

Hello:

I am trying out Language Cloud and attempted to migrate a TM to the cloud. SDL Trados notifies me that the migration failed. I looked at the details in the error notification, but what they said did not give me an indication of the cause of the failure, or how to fix it. I saved the details into a file which I have attached. Please help.

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