Two monitors through vga works, through dvi-d - no. why?

Question

Video cards

Motherboard Asus H81M-K. Features:
Integrated Graphics Processor Intel HD 4600
Multi-VGA output support : DVI/RGB ports
- Supports DVI-D with max. resolution 1920 x 1200 @ 60 Hz
- Supports RGB with max. resolution 1920 x 1200 @ 60 Hz
Maximum shared memory of 1024 MB
Supports Intel® InTru™ 3D, Quick Sync Video, Clear Video HD Technology, Insider™
two monitors (models don't matter to me) on one HDMI and VGA on the other VGA and DVI-D. Accordingly, I connect one cable via VGA-VGA and the second cable via DVI-D-> DVI-D. There is an image on the monitor connected via VGA, but the second monitor does not seem to see it.
Disconnect-connect DVI cable on the motherboard - everything is fine. Both monitors show. After a reboot, only one works again.
how to treat it? And what influences such behaviour?

Answer 1

anyone please help :)