Wifi do not provide internet

[Javi_pg]

Hi, 

I have noticed that internet (via WiFi) is very slow, and constantly when using internet, my devices ( all of them)  tigger a message saying that WiFi is not connected to internet and if I wanted to switch to cellular data, like I'm loosing the WiFi signal, even though when it looks like the signal of full (3 bars). 

could you have a look and solve the problem? Please 

[JimM1]

@Javi_pg Will not be the signal strength but the indication that there is NO Internet supplied, then asking to switch over to the mobile network. Have a look on the mobile to see if you have the !mark in the bars...