Over the last week, I've had the above error on two different SQL Servers, in different tenants and subscriptions, both UK South.
The error then also included: SqlError of "http://System.Data.SqlClient.SqlError: A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.)"
Google suggests it's a network issue. I have no clue where to start investigating.
All help much appreciated