ID:181043 Output port <port_name> of <atom_type> atom "<atom_name>" has one or more illegal fan-outs.

CAUSE: The specified output port of the specified PHY_CLKBUF atom is connected to one or more invalid atom destinations. This destination atom cannot be driven by a PHY_CLKBUF in the targeted device family.

ACTION: Consult the sub-messages for more information on which connections are illegal.