Support not sticking to Layer

Dremel 3D45
Dremel Diglab Slicer 1.2.3
Esun filament PETG 1.75 dia, net weight 1 KG, print temp 230 to 250 C, bed temp 70-90 C

I am printing a phone stand 75 CM high 75 cm Wide with 60 degree angle, base 83/75 CM, its an equilateral triangular stand with a hang of 10 cms angle of 30 degrees to hold the phone on the right of the phone stand.
the base is printing well, however the support required for the drop is breaking off and does not reach 1 to 2 cms

Any help on what I need to do the make the support adhere to the layer which is 5 cm high

I have tried increasing the print temp to 270 and the bed to 90 degrees same result