If you want to troubleshoot the 44 pin then you can try flashing a basic sketch to the board that just does an analogwrite to the 44 pin with a value of 127, lots of examples of analogwrite command on arduino site. That should get you a reading of about 2.5 volts on the pin. If that doesn’t work then your 44 pin may be damaged. At that point I’d try switching to 42 pin instead. Same instructions, just use pin42 instead of 44 in the pin assignments and connect ttl to that pin instead.