I'm using the OracleConnectionStringBuilder, from Oracle.ManagedDataAccess.Core 23.6.0, to create a connection string with the following code:
OracleConnectionStringBuilder stringBuilder = new OracleConnectionStringBuilder();
stringBuilder.Add("Data Source", "test");
stringBuilder.Add("User Id", "user");
stringBuilder.Add("Password", "ABCDefgh1234+_");
The stringBuilder will put the password value in curly braces, which the OracleConnection doesn't like, it always will return a bad credentials error. If I manually modify the created connection string to replace the curly braces around the password to be double quotes, it works fine.