It is like you do not have permission to create a database on the SQL Server instance, as indicated by "Exception Info: Microsoft.Data.SqlClient.SqlException (0x80131904): CREATE DATABASE permission denied in database 'master'."
To quote the following article https://dba.stackexchange.com/questions/78388/create-database-permission-denied-in-database-master-unable-to-get-the-permis
The user must be a member of
dbcreator server role for user to have enough permissions to create a database.
You can execute the following statement to make a user member of
dbcreator server role.
EXEC master..sp_addsrvrolemember @loginame = N'Shubhankar', @rolename = N'dbcreator'
sysadmin role are by default members of
dbcreator server role therefore they can create databases too.
Hope this helps.