I have an error like "errorKeyword not supported: \u0027metadata\u0027

Hello

The error, Keyword not supported: 'metadata' is because you are not passing correct connection string, you are passing Entity framework Connection string that contains a SQL Server connection string in its provider connection string parameter. WebSecurity.InitializeDatabaseConnection expects a valid database connection string.

Please try below connection string it should work.

ConnectionString is of EntityFramework Type. you can remove metaData and then getting the complete connectionString.

Use below connection string. 

Thanks

Replace all the " with the normal single quote character.