ID:169276 Cannot place GXB pin <name> with high data rate at location <name> -- possible switch coupling with <number> pin(s)

CAUSE: You assigned the specified I/O pin at the gigabit transceiver block (GXB) transmitter pin location in the device. However, the Fitter cannot place the pin at the location because of a possible switch coupling with other pin(s).

ACTION: Delete or change the location assignment, change the I/O standard assignment, or select the same target device with a different package.