had this happen to us on our Palazzo - the AutoZone near us had the butyl adhesive to do this. only had it in the caulk gun tube so look elsewhere - Amazon if you have the time to wait - I think it was $27.00 or so for the tube. We cleaned the glass and found it was originally installed backward - smooth side should be in for the holding power. clean up the class and get all the residue off the glass and window. when you glue the window (do both the window and frame - well I did) , leave two weep holes for any condensation to drip out rather hen leak into the door. Follow the instructions but use painters tape - blue one, to hold the window in for 24 hours for the glue to set up. Hope this helps and good luck.
Chuck and Mary Ann
FMCA, Good Sam Life Member and Thor MC member
Enjoy the journey, one day at a time!