Building react app after merge request on debian and copying the build with a custom user into the web folder keep failing

I have created a user that mounts its home folder into /var/www/subdomains.. folder via fstab. I have successfully installed gitlab-runner and I have also successfully connected it with GitLab. When it comes to deployment, I get this log:

Running with gitlab-runner 15.5.0 (0d4137b8)
  on React runner TxqfiVQT
Preparing the "shell" executor
00:00
Using Shell executor...
Preparing environment
00:00
bash: bash: command not found
ERROR: Job failed: prepare environment: exit status 127. Check https://docs.gitlab.com/runner/shells/index.html#shell-profile-loading for more information

.gitlab-ci.yml in the repository/files of the project

stages:          # List of stages for jobs, and their order of execution
  - deploy

deploy-job:      # This job runs in the deploy stage.
  stage: deploy  # It only runs when *both* jobs in the test stage complete successfully.
  environment: production
  script:
    - echo "Deploying application..."
    - echo "Application successfully deployed."

/etc/systemd/system/gitlab-runner.service

[Unit]
Description=GitLab Runner
ConditionFileIsExecutable=/usr/bin/gitlab-runner

After=syslog.target network.target

[Service]
StartLimitInterval=5
StartLimitBurst=10
ExecStart=/usr/bin/gitlab-runner "run" "--working-directory" "/home/custom-user/react" "--config" "/etc/gitlab-runner/config.toml" "--service" "gitlab-runner" "--user" "custom-user"







Restart=always

RestartSec=120
EnvironmentFile=-/etc/sysconfig/gitlab-runner

[Install]
WantedBy=multi-user.target

Thank you in an advance for your replies!