Hi @ajb2k3 thanks for your reply!
I have already reinstalled the firmare several times but the result does not change. Only a new API Key is generated.
I've been having this problem for several months now.

Hi, I can't connect my Core 2 to the UIFlow Web anymore. The WiFi and cloud icons appear green on the device, but when I try to enter the API Key on the website, the message "Upload code failed, maybe your device is offline check it and retry" appears.
I remember changing things on the M5Stack Device Platform website and now I no longer see my device listed.
Can you help me reset things?
Thank you!