Dear customer ,
Thanks for support.
For your info, the are lots of reason that why suction cup is drop. it is possibly due to microscopic pores or uneven spots in the surface on the surface.
You may try the below way to make it better stick
Clean the surface and the inside of the suction cup. Wipe up all dust and dirt which prevent an air-tight seal from forming. Use alcohol as a glass and surface cleaner to remove all grease and oils from the surface and from fingerprints.
Wipe the entire cleaner off with paper towels to avoid getting fabric fibers on the cleaned surface.
If necessary, wash the suction cups with warm, soapy water and pat them dry. Then, clean the surface before sticking the suction cups onto it
Push the suction cup against the surface until all the air bubbles inside are released and a vacuum is created. Suction cups stick better when the surface to which they are stuck and the suction cups themselves are clean and free from dirt