The hole spacing is too small.

If the hole spacing is too small, exceeding the manufacturing range of the standard 1oz copper thick plate, it will lead to a failure in the audit.

According to the manufacturing capabilities of PCBasic:

The minimum spacing between PTH (through holes) in different networks is 0.45 mm;

The minimum spacing between Via (over holes) in different networks is 0.30 mm.

If the hole spacing is less than the above values, it may cause problems such as drill deviation, short circuit on the hole wall, or insufficient electrical clearance, thereby affecting electrical safety and the reliability of the finished product.

PCBasic suggests:

Reduce the aperture appropriately to meet the minimum hole spacing requirements:

Through-hole (PTH): Spacing ≥ 0.45 mm

Via (Through-Substrate): Spacing ≥ 0.30 mm

Adjust the layout to increase the distance between holes, ensuring compliance with design rules. Of course, if your design has specific space limitations, please note them in the order remarks. We will conduct a manufacturability assessment based on the actual situation.