Persistent connection string errors .NET Core

I am migrating a full framework application to .NET Core. Under the full framework, it used the following connection string with the IBM .NET Connector for DB2:

"Server=localhost:50000;Database=testdb;" 

The code then assigned UserID and Password properties from credentials vault.

Now, under Core, with the IBM .NET Core connector for DB2 specifically v.2.0.0.100 (long-term support, according to IBM), this connection string throws an exception when a connection string builder is created from it:

{System.ArgumentNullException: Value cannot be null.    at System.Threading.Monitor.ReliableEnter(Object obj, Boolean& lockTaken)    at IBM.Data.DB2.Core.DB2ConnPool.ReplaceConnStrPwd(String value, String newvalue, Boolean onlyPwd)    at IBM.Data.DB2.Core.DB2Connection.RemoveConnectionStringPassword(String value, Boolean bMask)    at IBM.Data.DB2.Core.DB2ConnectionStringBuilder..ctor(String connectionString) 

There is no InnerException. I presume that some mandatory parameters of the connection string that I am not aware of have to be populated under Core, whereas under full framework they were optional. A careful read of IBM documents on DB2 connector Core yielded no mentions of connection string changes, unless I missed them. This blog post mentioned no such breaking changes.

Is anyone aware of mandatory connection string parameters that are missing from my connection string specifically for .NET Core connector?