Teensy LC not recognized with Teensy loader

[tifmmfz]

I connected my newly purchased Teensy LC board to Mac and tried to use Teensy loader to load LED blink for a quick sanity check. After I pushed the button, the orange LED stopped blinking, but Teensy loader remained at the page "Press Button on Teensy to manually enter Program Mode".

Setup: Teensy with microUSB to USBA adapter and Apple USB-C Digital AV Multiport Adapter
OS: MacOS 11.3.1 Big Sur

Any suggestion? Thanks.

[PaulStoffregen]

We've seen this exact problem over and over. It's almost always a charge-only USB cable.