The debug shows that this router is running BGP and is attempting to open a connection to a neighbor (which is what you described - the debug confirms it). I do not see anything here that indicates that there is a problem on this router. What the debug shows is that this router is not receiving any response from the other router. I suspect that the issue is on the other router. I suggest that you check the configuration of the other router. It is especially important to verify that the other router is configured for BGP, that it has a neighbor statement for this router, and that the router does not have any access list filtering which would not permit the BGP packets.
I think it does not matter which vendor router you are connecting to. You are sending the TCP SYN packet in initiate a connection and it looks like they are not responding. So the question is why are they not responding. The mechanics of how you configure it and how you check it are different by vendor but the question of why they do not respond is fairly universal.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...