HEROKU: Logging in with another Heroku accnt and deploying fails my build - express

Question

UPDATE:
I removed the warning by switching bcrypt versions V3 with V1.03. BUT now my passwords don't work. I assume it's because of the different hashing between both versions.
I created a personal Heroku account and uploaded my MERN project without a problem. I then created a 2nd Heroku accnt for work.
I then heroku logout and heroku login with the new account. I then tried uploading the same project with no changes, but keep getting
bcrypt#3.0.2 install /tmp/build_c823e78c1ca132209f395f59cc6e1071/node_modules/bcrypt
node-pre-gyp install --fallback-to-build
// lots of node-pre-gyp ERR! code before finishing with
gyp ERR! cwd /tmp/build_c823e78c1ca132209f395f59cc6e1071/node_modules/bcrypt
gyp ERR! node -v v8.12.0
gyp ERR! node-gyp -v v3.8.0
gyp ERR! not ok
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! bcrypt#3.0.2 install: `node-pre-gyp install --fallback-to-build`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the bcrypt#3.0.2 install script.
Node v8.12.0
NPM 6.4.1
Git version 2.17.1 (Apple Git-112)
macOS Mojave V 10.14

Answer 1

I use bcrypt 3.0.2 and ran into a similar issue today. Locally I am using Node version 10.11.0, but because I haven't specified it in the package.json, Heroku took a default Node version 8.XX.XX. I set it explicitly for Heroku as the same version as I use locally in my package.json file and then it worked.
{
"name": "my-app",
"version": "1.0.0",
"description": "",
"engines": {
"node": "10.11.0"
},
"scripts": {
...