PA28 Student Pilot reported an NMAC event during cruise on ATC flight following. Student Pilot executed an evasive maneuver when ATC stated traffic was on a conflict course.

Narrative

I was flying westbound (Heading 273) in Aircraft X at 4500 ft. MSL (the appropriate VFR Altitude per Part 91.159) when I saw on the iPad another aircraft within my ADS-B bubble traveling on an intersecting path to me; indicating 4250 on the iPad. (I was using a portable ADS-B receiver linked to my mobile phone). Having received a transponder code from ZZZ Approach; I was receiving VFR flight following. About a minute after I saw the ADS-B target (I estimate XA:51AM); ZZZ Approach called and gave me a traffic alert for the aircraft; indicating it was 1 mile (possibly 2 miles; I can't remember) to my 10 o'clock; indicating 4500 ft; and said something along the lines of 'you might want to descend'. As I started to respond; I saw the other aircraft to my 10 o'clock at my exact same altitude; and heading straight for me. I immediately cut throttle and dropped 400 ft; passing directly under the other aircraft as it passed above me. I estimate that if I had not taken evasive action; we may have missed by less than 50 ft. The other aircraft did not appear to take any evasive action. Later I looked up the flight tracking data for both of our aircraft; and at XA:52 AM it shows both aircraft with the same GPS coordinates and 400 ft. separated in altitude. When I first saw the other aircraft; I was transmitting to ATC; and said something along the lines of 'Oh shoot; he's on my exact altitude!'; and then I may have reported afterwards that we were clear of each other; but I'm not sure. I tried listening to the ATC logs; but none of the audio transmissions on there were audible.