Please try the below steps to set the touchpad first:

‒ Open the Touchpad and Click Function Settings:

• Click on the Apple logo, then select "About This Mac"
• Click on More Info
• Click on Trackpad to access gesture settings
• Enable Tap to Click to activate touch clicking

‒ Three Finger Drag Function Settings：

• Click on "Accessibility" to enter the settings page
• Click on "Trackpad Options"
• Enable "Use trackpad for dragging" and select Three Finger Drag

--Change another USB/Type C port or try to connect the T1-A Touchpad to other devices to check if the problem persists.

--Try another cable to connect the T1-A Touchpad to your device.

Recently, Apple computers have upgraded to the latest system, which has introduced some minor bugs that can affect the functionality of some gestures on the T1-A wired trackpad.

If your MacBook's system is upgraded to the latest macOS 15 or above, it may cause some trackpad gestures to be unusable. Here are a few solutions:

1. Use the trackpad on a computer with a lower version of the system (between macOS 10.11 and macOS 14) for a while, and then it should work again when connected back to a system with macOS 15 or later.
2. Try restarting your computer with the wired trackpad plugged in.
3. Unplug and replug the trackpad multiple times.