When I plug a projector to the VGA output, the system doesn’t detects anything. HDMI output works fine and I can set mirror view, extended desktop, etc. VGA output works fine in Windows and elementaryOS (also installed on the same machine). Arandr and xrandr show “disconnected”. Video driver is i915 (my laptop uses Intel HD5500 graphics).

Any idea? what can I check?

PS. This is my xrandr output with the VGA cable plugged:
Screen 0: minimum 8 x 8, current 1366 x 768, maximum 32767 x 32767
eDP1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 340mm x 190mm
1366x768 60.03*+
1280x720 60.00
1024x768 60.00
1024x576 60.00
960x540 60.00
800x600 60.32 56.25
864x486 60.00
640x480 59.94
720x405 60.00
680x384 60.00
640x360 60.00
DP1 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)