Main phone no Internet while other devices have

@Mectors 

Is it connected to the wifi but no internet access or it cannot connect to the Deco's wifi? 

Try to forget the network and reconnect to it and verify whether it works. 

WIth it connected to the Deco's wifi, please ensure that it can get valid IP address from the Deco.

And please notice that you haven't added it to  the blacklist on the Deco app. 

Still the same, please tell us the model number of your smart phone. 

Best regards.