GH5 The rubber has come off the SD cover. How can I attach it?

[FoxAdriano]

Hi,, I don't know if it is the heat problem but the rubber of SD cover came off. It is around 2cm and I don't know as I can glue it. I tried with a yellow mastic but it looked like water. It was impossible to glue it. The mastic was not able to glue the rubber, even it seemed that I had put water instead of the mastic. Yet that mastic is a formidable glue. Do you have some suggestions? Thanks

EDIT: I used it: https://www.amazon.it/UHU-B2_064503...546710760&sr=8-1&keywords=mastice+superchiaro