A fairly common mistake is using "SoftwareSerial SerialBT(RX, TX);" instead of "SoftwareSerial SerialBT(TX, RX);"
Dear @Passos_0213 , where you've found that information ?
On the SoftwareSerial library official web site
(https://docs.arduino.cc/learn/built-in-libraries/software-serial/)
the correct syntax is:
And care shall be taken to select the pins on the Arduino boards to be capable of supporting that feature.
Merry Xmas to all. 
Did you test it?
Nope.
I mean: I've always (i.e. in tenths of Arduino applications) followed the rule of the standard documentation, so why would I have used the reversed configuration (Tx instead of Rx) ?
So let me ask again where have you found that info ?
EDIT: a comon error is, instead, to forget to cross the wires (Tx to Rx) between Arduino CPU board and the BT shield, but as far as I can see in the snapshot of the wiring, this is not the case.
Don't think that is the issue since I am able to connect from my phone via a BT Terminal app and issue commands successfully.
The wires are crossed.
Yep, as I've said, according to your snapshot, they are correctly wired (and with SBT the Arduino side is working).
Have you removed the clock ?
Cheers.