Just as important as a good adhesive is to make sure you prepare the 2 surfaces properly or the best glue in the World won't stick. Try using some white spirit but obviously be careful it doesn't splash onto the paintwork.
white spirit first(good advice s6boy)remove all the old adhesive re apply with sickaflex (3m product) ,be sure to wear gloves it sticks to everything and gets fu#k1n everywhere