ID:16768 Can't use existing clock buffer for mandatory global fanout at node "<node>". Ensure that the global signal types are consistent in your design and that the existing clock buffer can drive the required global destinations without violating partition boundaries.

CAUSE: Fanout sourced by the specified node must use the clock network, but an existing clock buffer at the node is incompatible with the global signal type.

ACTION: Ensure that the global signal types are consistent in your design and that the existing clock buffer can drive the required global destinations without violating partition boundaries.