Network disturbances in glassfiber ring setup

Hi all,

I have never tried looking for advice this way, so I'm just giving it a shot because why not! Feel free to ask me anything if you feel my explanation is lacking information.

I am a full-stack developer and have basically been given responsibility over the complete enterprise network of a campus consisting of 4 buildings with 100+ workplaces per building. The downside is that I'm not specialized in networking. This is not really a problem when things go according to plan, but recently we have been experiencing some network downtimes which I feel are out of my league.

The buildings are all connected in a glassfiber ring setup with Huawei managed switches. There are approximately 10 VLANs which are mainly specific to certain offices, but 1 VLAN goes through the complete ring which is used by production to offices for the main company which owns all buildings.

Recently there have been major 'hickups' in the network. The access-control system sends out a mail every time a doorcontroller is unreachable, this way I monitor network connectivity real-time. We don't have a good implementation of real monitoring software, which is a desire we have for the future.

To pinpoint the source of the problems, we have started disconnecting the glassfiber ring to rule out faulty wiring. So in the 'new situation' we don't have a circle anymore but rather two branches (let's call them A and B) from the uplink. Branch A has no issues at all, whereas branch B has major hickups in connectivity.

What I find curious; the hickups occur in the segment on the bottom of the branch.

So let's say switch X is the end-point of branch A and switch Y is the end-point of branch B. In this setup switch Y is experiencing major connectivity issues. When I connect Y to X and disconnecting X from branch A, the new situation is that Y is no longer the end-point of branch B, X is now the end-point of branch B. This change shifts all connectivity issues of Y to X, leaving section Y function completely stable.

So we experience the end-point of branch B to be problematic, whether the end-point is X or Y.

I would really appreciate some advice to find the cause of this. Any advice at all, is greatly appreciated. At this point I am even willing to swap out all hardware and rebuild the complete network.