Programming Homelink on Liftmaster 8500 issues?

Finally got around to programming the Homelink in my '15 Cayenne Diesel. I have 3 seperate doors with 3 seperate openers, so one for each Homelink button. Two openers are standard Liftmasters, center door is a vertical opening jackshaft liftmaster 8500.

After a few fits and starts I got both the "regular" openers programmed into Homelink. However I can't seem to get the 8500 to sync up. I'm tapping the "learn" button on it twice so the red led pops on, then holding down the Homelink button until I get a slow flashing light. Then going in front of the truck and holding down the proper remote button until the turn signals flash three times. I then hit the button on my original remote, then try the Homelink button. No love. Tried it a few times, same thing.

What am I missing? Of course that opener is the door where I park...

I have no advice for you, but I have successfully paired Porsche Homelink systems with Liftmaster 8500 openers, so I know that it can be done.

I had issues with an 8500 talking to an '011 Audi. Tech support at Liftmaster said they were compatible, but after repeated attempts I ended up purchasing a repeater:

https://www.amazon.com/LiftMaster-855lm-Homelink-Repeater-Kit/dp/B01GWD4LUI

The signal seems to be weaker with the vehicle homelink button than the Liftmaster clip-on, but it works.

Good Luck!

I already have the repeater installed, needed it for my old Cayenne and my wifes current car.

I got it to work tho, everything remained the same but this time the truck was inside the garage vs being out in the driveway.  Only thing I can think of is that since the learn button on the 8500 is on the wall panel, not the opener, which is near the entry door of my house, the distance was too far for the signal to make it while learning when the truck was in the driveway?