I thought I'd asked this before, but can't find it. When I connect my iPhone (old SE) to my MacBook Pro (2014), in order to transfer some photos, the MBP opens Apple Photos fine. But then the MBP Photos screen alternates between Library and iPhone, while the iPhone itself beeps about once a second, occasionally briefly flashing up a window asking whether I trust the MBP. I have not been quick enough (or the window doesn't last long enough) to press the "Trust this computer" button. I can't find a seting on the iPhone or the Mac that would resolve this. The Mac is on Big Sur 11.6.3 (apparently I could update to 11.6.5) and the iPhone is on IOS 15.3.1 (could update to 15.4).
Any ideas, anyone?