ID:12407 Output port <name> of I/O output buffer "<name>" has too many fan-outs. The I/O output buffer is allowed to drive only one top-level pin, but the I/O output buffer has <number> fan-outs

CAUSE: The specified I/O output buffer primitive has too many fan-outs. The output buffer can drive only one top-level pin.

ACTION: Connect the specified I/O output buffer primitive to only one top-level pin.