Bot not working

I added the Stale bot to some of my repos a couple of weeks ago, but it didn’t to anything to the open issues. I’ve changed the yaml file a few times to see if it makes the bot work, but no luck. This is the current stale.yml file (in the .github folder of the master branch of each repo I’d like the bot to work in):

# Configuration for probot-stale - https://github.com/probot/stale

# Number of days of inactivity before an Issue or Pull Request becomes stale
daysUntilStale: 15

# Number of days of inactivity before an Issue or Pull Request with the stale label is closed.
# Set to false to disable. If disabled, issues still need to be closed manually, but will remain marked as stale.
daysUntilClose: 7

# Only issues or pull requests with all of these labels are check if stale. Defaults to `[]` (disabled)
onlyLabels: []

# Issues or Pull Requests with these labels will never be considered stale. Set to `[]` to disable
exemptLabels:
  - pinned
  - security
#  - "[Status] Maybe Later"
  - pending

# Set to true to ignore issues in a project (defaults to false)
exemptProjects: false

# Set to true to ignore issues in a milestone (defaults to false)
exemptMilestones: false

# Set to true to ignore issues with an assignee (defaults to false)
exemptAssignees: false

# Label to use when marking as stale
staleLabel: staledByBot

# Comment to post when marking as stale. Set to `false` to disable
markComment: >
  This issue has been automatically marked as stale because it has not had
  recent activity. It will be closed if no further activity occurs. Thank you
  for your contributions.

# Comment to post when removing the stale label.
# unmarkComment: >
#   Your comment here.

# Comment to post when closing a stale Issue or Pull Request.
closeComment: >
  This issue has been automatically closed because it has not had
  recent activity. Thank you for your contributions.

# Limit the number of actions per hour, from 1-30. Default is 30
limitPerRun: 30

# Limit to only `issues` or `pulls`
 only: issues

# Optionally, specify configuration settings that are specific to just 'issues' or 'pulls':
# pulls:
#   daysUntilStale: 30
#   markComment: >
#     This pull request has been automatically marked as stale because it has not had
#     recent activity. It will be closed if no further activity occurs. Thank you
#     for your contributions.

# issues:
#   exemptLabels:
#     - confirmed

Any clues on what’s going wrong? Thanks!

[mbanon]

Funny, because this one said it was correct https://codebeautify.org/yaml-validator !

The bot just fired now, so THANKS! It worked 😃

<div>Best YAML Validator Online</div><div>Free YAML Validator is a web based validator and re-formatter for YAML. Also know as YAML Lint.</div>

[issue-label-bot[bot]]

Issue-Label Bot is automatically applying the label bug to this issue, with a confidence of 0.78. Please mark this comment with 👍 or 👎 to give our bot feedback!

Links: app homepage, dashboard and code for this bot.