Error (169079): Pad 138 of non-differential I/O pin 'pin93' in pin location F13 is too close to pad 136 of differential I/O pin 'APBLCLK(n)' in pin location G16 -- pads must be separated by a minimum of 5 pads. Use the Pad View of Pin Planner to debug.
For this issue, the placement of your pin is too close. The pad must be separated by min 5 pads.
solution: Use the Pad View window of the Pin Planner to check the pad placement, and then assign one of the conflicting I/O pins to a different location