SQL error when connecting to server using servername\instance.

SQL error when connecting to server using servername\instance. 

Error:

A network-related or instance-specific error occurred when establishing a connection to SQL server. the server was not found or was not accessible.Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error:26 - Error Locating Server/Instance Specified) (Microsoft SQL Server)

 

 Solution:

The UDP port 1434  on destination server was being  blocked in  the firewall.

Cannot open backup device. Operating system error 5(Access is denied.). RESTORE HEADERONLY is terminating abnormally. (Microsoft SQL Server, Error: 3201)

Came across this error while trying to restore a SQL database backup which was stored in a container to Azure SQL managed instance.

Operating system error 5(Access is denied.).
RESTORE HEADERONLY is terminating abnormally. (Microsoft SQL Server, Error: 3201)

The blob would connect properly and show the backup file.

Solution:

Deleted the stored credentials in the database and did the process again for restoring backup.