One possible reason is a misconfigured enabled & preferred VISA configuration.
Check the VISA Conflict Manager settings in your vendor's software
- NI MAX for NI VISA
- Keysight Connection Expert for Keysight VISA
Make sure that at least one VISA implementation is enabled and that one is set as preferred.
For example in Keysight Connection Expert, you can open the VISA Conflict Manager and change the settings as recommended.
*After you made the change, don't forget to save the changes made after exiting it.