Cannot connect Blub v1 anymore

Hello guys,
I cannot connect my Yeelight Light Color Bulb v1 anymore. I tried different smartphones, the mihome and the yeelight app. Also different wlans. I also placed the bulb next to the router. Im sure the password is correct. Also I tried different servers.

Everytime I reset the bulb. The mihome App says, that the “connecting to network timed out”. Also the yeelight app tell me this failure.

What can I do?

Best regards

How about setup a hotspot with 4G network and connect bulb to it?

If yes, please try to change your router’s DNS server to Thanks.