3M Super Trim Adhesive. Are you trying to glue the old headliner back
up? That won't work as the foam backing just deteriorates.

I had the same problem.
In the end, I decided to stitch the cloth to the board.
The board already has holes in it, so that makes it easier.
It's quite some work, but with two people, each on one side
of the board, you can do a really thorough job with thread
and needle.

  Bram

I haven't a clue.
We are on our third headliner in our 1987 Camaro.  Do you think that maybe
GM coated the roof with
something that de-activates glue after a period of time?
Graybeard

Solutions that have worked for me.
Pull down the headliner. Scrape it clean. Go to a local auto upholstery shop
and buy a replacement foam and uber thin cloth OEM style replacement. Use 3M
Super Trim adheasive spray to put it on.

Option two, do the same as before BUT, with these changes. When you have the
headliner clean, paint it. It helps build up the headliner and make a better
adheasive surface. Then, skip the auto shop and go to a local fabric shop
and buy several yards of felt. It comes in a lot of colors, doesn't have the
self destructing foam, and seems to last a lot longer. Proceed with the 3M
ST spray.

Best of luck and merry Christmas.