Oh... That's such a GREAT question : )
Let's start here. This does not look good...

[TAILING] Tailing last 15 lines for [engwit] process (change the value with --lines option)
/home/ubuntu/.pm2/logs/engwit-error.log last 15 lines:
0|engwit   | Error: EACCES: permission denied, open './config.json'
0|engwit   |     at Object.openSync (node:fs:492:3)
0|engwit   |     at Object.writeFileSync (node:fs:1516:35)
0|engwit   |     at Object.writeFileSync (/home/ubuntu/apps/steemsmartcontracts/node_modules/jsonfile/index.js:117:13)
0|engwit   |     at saveConfig (/home/ubuntu/apps/steemsmartcontracts/app.js:170:6)
0|engwit   |     at stopApp (/home/ubuntu/apps/steemsmartcontracts/app.js:175:3)
0|engwit   |     at runMicrotasks (<anonymous>)
0|engwit   |     at processTicksAndRejections (node:internal/process/task_queues:94:5) {
0|engwit   |   errno: -13,
0|engwit   |   syscall: 'open',
0|engwit   |   code: 'EACCES',
0|engwit   |   path: './config.json'
0|engwit   | }