I noticed that some of dipole sources/monitors are located outside the ring. Also, since the ring that you were working with was large (radius~30um) and simulation were taking a long time, I tried to focus on a simpler case of a ring with radius of 2um. Ultimately my goal is to simulate your case, but since this is my first time simulating a ring resonator I thought it will be easier to start with a simpler case. Also, I removed the waveguide to study only the ring resonator (external waveguide might effect the quality factor and frequency of resonant modes but not the physics and our strategy).
I have my simulation file attached with the screenshots of first resonance:
RingResonatorRadius2um.fsp (300.9 KB)
Please note that the strength of the peak depends on the location of dipoles and monitors (here I located them all in the fist quarter as I was planning to use symmetry later on but you can randomly locate them at any point on the ring resonator).
Please go ahead and modify your simulation file. I am working on your case but it might take a while for me to get back to you as optimizing your devices for larger ring might take a while.
Also, do you have a reference for your simulations? It should give us intuition on how we can optimize the dipoles and monitors to capture the modes properly.