When using SFTP with Azure Blob Storage, the user name setting is indeed storage_account_name.localusername1 ,This format cannot be changed or removed. The prefix ensures that the SFTP client can correctly identify the storage account and local users.
One possible work around is to see if you can configure your system to accept this username format. Alternatively, you might consider using a different method to capture this unlimited data.
Please go through the below given links:
If you need more help, don’t hesitate to ask!