It is frustrating when you cannot connect to ADB.
Here is a list of troubleshooting items:
Developer Options - ADB
The first one is obviously enabling ADB in Settings > Developer OptionsUSB role
The USB role for ADB should be the "Device", your computer is the "Host".
- Device
- this device is powered by the USB
- this device can send ADB data to the Host
- Host Mode
- this device powers the USB
- this device sends and receives the data
- Accesory - this device cannot be a "Host", but acts like one
- this device powers the USB
- this device sends and receives the data
Correct DATA USB cable (and hubs)
This one gets me the most often, once you verify that the USB cable works label it.
The same goes for any hub or USB C to USB A converter.