I have a problem with my camera , after a few seconds automatically stops recording as you lose the connection with the iPhone and the sound is cut off before it stops recording

Hi, is this happening when recording with 4k or1080? also what FW do you have installed on the osmo?
Maybe even try to change the phones wifi (app) setting to 5.8ghz, also close all other applications on your phone when using the dji go app for the osmo

If you can exclude the possibility of the mobile device, DJI GO App or WiFi signal, then please try to test the SD card of the Osmo.