1. As I explained for several times, we could not check the logs during the remote session. It is impracticable since your network speed is very very slow. However, I will try again if you could copy them to another support PC which network speed is fast enough.
2. Before then, please, verify following information.
A. When you have changed the dial mode to Preview?
B. What is the original dial mode before changing to preview?
C. What is the Service name and contact List name?
D. How can you recover it? Restarting any service or resume to normal automatically sometime later?
3. By the way, please, note that even if you change the dial mode to preview, agent could not get preview call immediately. The reason is, there should be many calls queued on cache before changing the mode, and hence, the dial mode will be changed after all the calls in queue were completed to dial out.
4. Please, try to reproduce the issue and wait for some more time to check if agent could get screenpop.