I thought I'd post this here in case anyone else ran into the same problem.  After upgrading to SolidCP version 1.4.1 I started receiving errors in SolidCP whenever I tried doing anything with a MySQL database.  (Not sure if it makes any difference, but I'm using MySQL 5.7)  I finally determined the error was caused by the setting "Set SSLMode to None" in the MySQL Service Configuration.  Checking the box fixed the problem.  In the upgrade this setting must have been set to null instead of 0 or 1 in the SolidCP database.  
This is the error I received when trying to add a new database.

System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.ArgumentNullException: Value cannot be null.
Parameter name: value
at System.Boolean.Parse(String value)
at SolidCP.Providers.Database.MySqlServer.get_SslMode()
at SolidCP.Providers.Database.MySqlServer.get_ConnectionString()
at SolidCP.Providers.Database.MySqlServer.ExecuteQuery(String commandText)
at SolidCP.Providers.Database.MySqlServer.DatabaseExists(String databaseName)
at SolidCP.Server.DatabaseServer.DatabaseExists(String databaseName)
--- End of inner exception stack trace ---
at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall)
at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
at SolidCP.Providers.Database.DatabaseServer.DatabaseExists(String databaseName)
at SolidCP.EnterpriseServer.DatabaseServerController.AddSqlDatabase(SqlDatabase item, String groupName)