Skylab1 i am sorry I don’t understand how does FOV solve my problem.
I think the ZWO person assumes that you are using an ASIAIR, which has limitations on what it can solve.
Compute your FOV from the focal length of your OTA and the sensor size that you are using. A reasonable approximation of the FOV in degrees is the sensor dimension divided by the effective focal length, and multiplied by 57.3.
If that FOV is too small (i.e., the smaller side of the FOV is smaller than 0.2 degrees if you are using a Raspberry Pi 4 based ASIAIR, or 0.4 degrees for a Raspberry Pi 2 based ASIAIR), you will not be able to plate solve.
If your current FOV is too small, you would need to add a suitable focal reducer for your OTA, and/or use a camera with a larger sensor chip.
If you have an FOV that is too small for ASIAIR's database, you can always use astrometry's web tool to plate solve for you: