Reason A : Changing your label type and size are the main causes for printer skipping labels or continuously feeding
First step：
Disconnect the USB from your printer. Check  "Feed" Button.
Let the printer re-learn your label (please refer Why Same label keeps printing? (AM-243-BT) ). Then change your label type, size on your computer, then re-connect the USB to the printer.

Second step：
For MacOs:

Select or input label width and height that matches label size installed in printer in prompt window. (Please refer How to create a new 4x6 inch label size on Mac? (AM-243-BT) )

For Windows:

Go to "Control panel" -> "Devices and Printers"

(Right click on "This PC", choose "Properties", then click on "Control panel"-> "Devices and Printers")
-> Right click on Label Printer" -> choose "Printer Preferences" -> go to "Page Setup"

-> You can choose the size you need in "Paper Name".

-> If there is no label size you need; you can click "New" to create a label size.

-> Change Paper name and input width and height, click "OK"

(Please refer How to create a new 4x6 inch label size on Windows? (AM-243-BT))

Notice: The application you are using (i.e. Adobe Reader) could be over-riding your driver label setting and sending the print in a larger/smaller size to printer. Look for "Page Setup" or "Paper Size" in the print prompt and ensure it is set to the size you want.

Reason B: The sensor which detects the paper, is covered by dust and that causes the detection is incorrect
You can check this guide to know: How to maintain the print head (AM-243-BT)?

Turn off printer. Open the Cover and use the alcohol pads to clean the sensor. (Any 70% Alcohol pad would work.) Let 2-3minutes for components to dry, then close the Cover and turn Label Printer back on.