Two backup options:
BACKUP DB TO URL WITH CREDENTIAL - makes blob, requires credential to use token, not SAS, when creating [Cannot stripe backups across multiple files]
BACKUP DB TO URL [sans credential] - makes blocks, requires credential name to match the url [storage account + container], SAS in secret, [CAN stripe backups across multiple files]
Removing the leading '?' is hardly ever mentioned and stuffs everyone around.
Operating System error 50 (for me on Windows Server 2012 R2; sql server SQL Server 2016) is possible even when everything is correct: I have a job which backups dbs to Azure striping across files - failed 1 database on Friday, succeeded same db without changing anything on Saturday... just to add fuel to the fire.
It may be your authentication which is causing your failure to locate containers.
USE master
CREATE CREDENTIAL [https://<mystorageaccountname>.blob.core.windows.net/<mystorageaccountcontainername>] -- this name must match the container path, start with https and must not contain a trailing forward slash.
WITH IDENTITY='SHARED ACCESS SIGNATURE' -- this is a mandatory string and do not change it.
, SECRET = 'sharedaccesssignature' –- this is the shared access signature token
GO
Source: https://docs.microsoft.com/en-us/sql/t-sql/statements/create-credential-transact-sql.
/* Leaving this as historic context */
REFER "MSDN: SQL Server Backup to URL Best Practices and Troubleshooting"
I found your post because I too am struck with the 50 error, even after reading "MSDN: Tutorial: Using the Microsoft Azure Blob storage service with SQL Server 2016 databases"
I think you should access http://portal.azure.com and then login to your Azure subscription. You change "directories" from Trial to Pay-as-you-go in the top right of the screen...
BTW I think you may need Shared Access Signature in SQL 2016 because when I copy a SQL 2012 script {Backup DB X using CREDENTIAL Y} to 2016 instance, it fails (FORBIDDEN) DESPITE them saying you can use credentials...
Also, Operating System error 50 (The request is not supported), leads me to think server 2012 r2 may be the error... testing currently on my laptop (windows 8) yields same error.
Good luck.
Best Answer
I think this is a restriction of the free Azure account - try changing your availability zone to us north.