nextion dispay doesnt transmit

hi all,
I have started working with the nextion displays.
i worked with 2.4" basic display and moved to 7" enhanced.
im using a simple code to counter up/down with a touch buttons and the arduino sends back to the display the number.
all is well with the 2.4", but after "immigrating" to the 7", the arduino cant detect the transmition (it can only send information).
im using the arduino as well as a counter to see that there is communication and there is.....
any sugestions..... ??????

*Im using: ITEADLIB_Arduino_Nextion-master