Secure device

i can’t add my smartphone to the list of secured device. I downloaded and followed instructions.
on cell phone the avast app does show me connected to my email.

https://support.avast.com/article/210/ (Account FAQ)

I DOWNLOADED THE INSTALLER TO MY CELLPHONE.
STILL NOT LISTED! ONLY SHOWS MY PC.

https://forum.avast.com/index.php?topic=223836.0