I’ve encountered the same problem, I’ve used pro model daily, clearly it downgrades to 5.5-mini in recent days, did anyone finds out a solution?

I’m having the same issue: with the same account in the same country, the mobile and PC versions use different models. This issue cannot be ignored. People generally use Pro for important tasks, and secretly switching to Mini could cause serious losses to some people’s work.

I just wanted to write an update before I unwatch this thread. I’ve not had this issue for more than a week.

The fix on my side was IP reputation, i.e. VPN/ISP.

The boundary between success and failure was requesting IP address.

I found that not only does the “Send” message have to be sent from a high-reputation IP, but the actual hosting page load itself does, too. (i.e. `chat.openai.com` has to load with a good IP, and then your message “Send” does too.)

For me this involved creating permanent ChatGPT bypasses on my VPN for these domains’ traffic:

chatgpt wss.chatgpt ws.chatgpt auth.openai chat.openai challenges.cloudflare

(All ending in .com but omitted due to community formatting rules)

I hope this helps others!

Access to Pro models is critical for work, so sacrificing connection stability or IP privacy was a trade off that I had to accept.

The time boundary on this was sometime in May/June, as back in March/April using the same VPN provider was not an issue. I imagine it’s a bug in new model access protections (and China distillation countermeasures).