Is the keychain remote also a Craftsman or is it a "universal" brand?

What "learn" procedure are you using? It's takes different steps if
it's a universal brand.

Newer (less then 1 yr old) Craftsman openers are on a 315 freq (purple
antenna wire) & not the old 390 freq (gray antenna wire). If the
keychain remote is not Home Link (www.homelink.com) compatible & is on
the 390 freq it will not work on your opener at all. The same in
reverse, if the keychain remote is 315 & if the opener is 390 the
keychain remote won't work either.

Doordoc
www.DoorsAndOpeners.com