Error: "Net: Invalid input arguments" after upgrading database from 19c to 23c (4374481)

When using a database that was upgraded from 19c to 23c, Toad shows the following error: 'Error: "Net: Invalid input arguments"'

When the database was on 19c, it was possible to connect using Toad ("No-client mode").  Then if the database is upgraded to 23c, now the above error happens.

You can successfully connect to the 23c database if you use an Oracle client, but not in DIRECT mode, and can still connect to other databases in DIRECT mode, just not the upgraded one.

WORKAROUND:
You can successfully connect to the 23c database if you use an Oracle client, but not in DIRECT mode

STATUS:
Issue resolved in Toad for Oracle 2024 R2 - v24.2.275.4664 (Released on Nov 4th 2024).

The latest version of Toad can be downloaded here:

Windows

Mac