Push error when deploying discord bot on Heroku - heroku

Question

could anyone help me, please?
I know very little of programming, still, I managed to create a Discord bot for a server. Initially, it worked perfectly, but one day I couldn't deploy it on Heroku anymore when I made any change on the bot.
Here is the error message:
$ git push heroku master
Enumerating objects: 24, done.
Counting objects: 100% (24/24), done.
Delta compression using up to 4 threads
Compressing objects: 100% (19/19), done.
Writing objects: 100% (19/19), 1.75 KiB | 895.00 KiB/s, done.
Total 19 (delta 14), reused 0 (delta 0), pack-reused 0
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> Node.js app detected
remote:
remote: -----> Creating runtime environment
remote:
remote: NPM_CONFIG_LOGLEVEL=error
remote: NODE_ENV=production
remote: NODE_MODULES_CACHE=true
remote: NODE_VERBOSE=false
remote:
remote: -----> Installing binaries
remote: engines.node (package.json): unspecified
remote: engines.npm (package.json): unspecified (use default)
remote:
remote: Resolving node version 12.x...
remote: Downloading and installing node 12.19.0...
remote: Using default npm version: 6.14.8
remote:
remote: -----> Restoring cache
remote: Cached directories were not restored due to a change in version of node, npm, yarn or stack
remote: Module installation may take longer for this build
remote:
remote: -----> Installing dependencies
remote: Prebuild detected (node_modules already exists)
remote: Rebuilding any native modules
remote:
remote: > node-cron#2.0.3 postinstall /tmp/build_d666c44d/node_modules/node-cron
remote: > opencollective-postinstall
remote:
remote: sh: 1: opencollective-postinstall: Permission denied
remote: npm ERR! code ELIFECYCLE
remote: npm ERR! errno 126
remote: npm ERR! node-cron#2.0.3 postinstall: `opencollective-postinstall`
remote: npm ERR! Exit status 126
remote: npm ERR!
remote: npm ERR! Failed at the node-cron#2.0.3 postinstall script.
remote: npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
remote:
remote: npm ERR! A complete log of this run can be found in:
remote: npm ERR! /tmp/npmcache.Miyop/_logs/2020-11-16T21_23_56_325Z-debug.log
remote:
remote: -----> Build failed
remote:
remote: We're sorry this build is failing! You can troubleshoot common issues here:
remote: https://devcenter.heroku.com/articles/troubleshooting-node-deploys
remote:
remote: Some possible problems:
remote:
remote: - node_modules checked into source control
remote: https://devcenter.heroku.com/articles/node-best-practices#only-git-the-important-bits
remote:
remote: - Node version not specified in package.json
remote: https://devcenter.heroku.com/articles/nodejs-support#specifying-a-node-js-version
remote:
remote: Love,
remote: Heroku
remote:
remote: ! Push rejected, failed to compile Node.js app.
remote:
remote: ! Push failed
remote: Verifying deploy...
remote:
remote: ! Push rejected to gale-explorer.
remote:
To https://git.heroku.com/gale-explorer.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/gale-explorer.git'
Could anyone help me with a detailed step-by-step procedure?
Thank you so very much.