That also happened to our CY's front awning.
Because of our specific floorplan, windows, door, front taper of roof placement vs. the awning arm bracket placements, the front awning had to be lowered about 4" compared to the rear one. This assured that none of those awning rail screws were placed into anything substantial.... just the siding. Compounded with the fact that installers with power tools spinout screws by over-tightening, our awning started to let loose and ooze putty on both ends also.
The wife and I reattached it a month ago...it was a simple project as long as the wind doesn't "surprise" you when the fabric rail is completely disconnected for the rail/siding cleanup..
I flopped it out a foot from the siding, secured it, redrilled all holes a little larger for those blue drywall plastic inserts, hammered them all in, putty taped the rail, and reused original screws. This was a 2 person job to control the (2) rails with fresh putty installed (in the wind), so have your partner lined up ready for work!
I did it this way first for a trial fix as the rail is still easily removable this way. If it needs more drastic attachment measures, such as the 8-10 screws at each end (or all of them), I will remove one screw at a time, then drill holes for some black tri-tipped exploding pop rivets.
This was my biggest quandary of the entire project: Do I keep it simple with the inserts so to be removed easily, or go full-tilt and use the speciality rivets for a "permanent" install that would require drilling them out for rail to be removed.