Question about Xiaomi Mi Laser Projector 150"

Recently, the remote control suddenly stopped working. It cannot be "paired" again either. The whole thing happened shortly after the update to Android TV 9, Security Update August 2020. I replaced the batteries of the remote control with fresh ones, because my first assumption was that the batteries might be empty / too weak. The Bluetooth connection between the projector and other Bluetooth devices works (e.g. use the projector as a Bluetooth speaker on the iPhone or use external Bluetooth speakers on the projector). The remote control can be "paired" with the iPad without any problems and can also be used there to navigate in some menus etc. Today I tried to pair with the remote control of a colleague's Chinese model to rule out a defect in my remote control. --> It does not work either. Has anyone had a similar experience and perhaps even a solution? Thank you.