Youview problem with new smart tv

[#1]

I have just bought a TCL smart tv and set up my youview box the same way I set up with my old tv, which is the aerial into the box, the ethernet cable into the box and the box connected to the tv via a hdmi cable, I then went into the tv settings selected the programme for watching connected devices selected hdmi I could then access all programes using my youview remote no problem. After a couple of hours I switched from BT sport to itv but this time there was no connection I got a message saying internet not connected but I could access terrestrial tv by using the tv,s remote,the only way I can now get into the BT channels is by going into the tv settings selecting hdmi and I have the channels back but the youview remote dosent work for the terrestrial channels so im having to switch between remotes and having to keep selecting hdmi for my youview channels, as my internet connection is strong im at a loss as to why this is occurring not being great with this technical stuff im hoping someone with a better idea of the tech stuff might be able to throw some light onto this problem.

                                                                              Thanks.

[#2]

Your description of switching from BT Sport to ITV suggests you used the TV remote, so the TV reverted to aerial input (as I keep telling my wife!) and you do not have an TV aerial connection. This would also explain the "no internet" message, assuming your TV has an internet capability (are there any that do not now?) and why you need to re-select HDMI.

Phil

[#3]

Thanks for the response, when I switched from BT sport to ITV I used the youview remote as I used to do with my old tv but I just get a connection is weak or lost signal if I input a youview channel number on the remote then the tv programme returns, the only way I can then access terrestrial freeview channels is to use the tv remote choose input source select tv and all freeview channels show but I cant access apps as it shows network not connected. If I connect the youview box back to my old tv everything works fine just using the youview remote and the tv remote to access tv settings. I have to keep switching from tv to hdmi in source to be able to switch between internet channels and freeview channels. I don't understand why when in hdmi mode I cant access everything through the box, in tv mode I cant access youview epg unless I take the ethernet cable from the box and connect to the tv and vice versa,  thanks again.

[#4]

Quick update, I programmed my remote to also control the tv and that now operates everything and its all ok, good job I checked this morning as well as messing about last night I also left my aerial connected to the tv instead of the youview box, rectified that as well all ok. Happy New Year.