Can't flash outside

I have a d3100 and a SB-910. I tryed to fill flash today outside. But in P it would gie me a error message, like too bright. Also a HI would show on the screen.
Also I tryed M. but I had to go to 1/1000 to get the right exposure. But the flash would not let me go above 1/200. So I could not take the picture. Whenever I tryed to flash I was blocked. I jsut wanted a fill flash.

Yup, I believe the consumer bodies like the D3100 have both a slower max sync speed (1/200 vs 1/250) as well as lack High Speed Sync (the ability to shoot over the max sync speed).

Your best bet with that camera body would be one of two things ... close down the aperture so that the resulting equivalent exposure results in a shutter speed that does work with flash, or use an ND filter to lower the exposure so that the shutter speed drops below 1/250. There are pros and cons to both methods, but they'll at least let you shoot with what you have.

Camera P mode is normally the easiest with flash outdoors, even ideal. Pro wedding photographers call P mode Professional Mode, joking about how they can move from indoors to outdoors with flash without issue.

What were the details you saw? 1/200 second shutter, and what ISO and what aperture did it try?

If we try camera A mode in bright sun, we might not know to stop down aperture enough to avoid a HI error. But P mode will simply stop it down as needed. But if you set ISO too high, it will just need to stop down more, and might then hit a f/22 or f/32 limit of your lens. So try ISO 100 outdoors.

Saying, ISO 100 1/200 f/11 is Sunny 16 as expected in bright sun. But ISO 800 requires f/32, which not all lens can do. Try ISO 100. Should be easy.