Triggering 2nd Azure Pipeline After Successful Run on 1st pipeline

I have two Azure pipelines, A and B. I'm aiming to have pipeline B execute whenever pipeline A completes successfully, but I also want pipeline B to be triggered independently based on its own criteria. My second pipeline, B, is defined as follows:

trigger:
 - master

resources:
  pipelines:
  - pipeline: mySourcePipeline
    source: Source Pipeline
    trigger: true

pool:
  vmImage: ubuntu-20.04

steps:
- checkout: self
  submodules: true
  lfs: true

- task: NodeTool@0
  inputs:
    versionSpec: '18.x'
    displayName: 'Install Node.js'

- task: Bash@3
  inputs:
    targetType: 'inline'
    script: echo 'Second pipeline is triggered'

I'm following the guidance provided here: Azure Pipelines Triggers.

However, in my scenario, pipeline A completes successfully, yet the second pipeline (B) doesn't get triggered. What might be causing this issue?

Any insights or suggestions would be greatly appreciated!

What I'm aiming for is:

• The initial pipeline for setting up Azure infrastructure, including items like storage accounts and resource groups.
• The second pipeline to handle deploying and publishing content to the newly created storage account.
• The second pipeline, which will not only be triggered after the first one but also have its independent trigger. This means it can be initiated on its own apart from its connection to the first pipeline.

Assuming that first pipeline looks like

trigger:
  branches:
    include:
    - staging
    - production
variables:
- name: isProduction
  value: $[eq(variables['Build.SourceBranch'], 'refs/heads/production')]
- name: isStaging
  value: $[eq(variables['Build.SourceBranch'], 'refs/heads/staging')]

stages:
- stage: A
  jobs:
  - job: A1
    steps:
    - script: |
        echo "isProduction: $(isProduction)"
        echo "isStaging: $(isStaging)"
        echo "Build.SourceBranch $(Build.SourceBranch)"

And it is named firstpipeline (not the yaml file, but the name of the pipeline in Azure Devops portal).

Then your secondary pipeline should look like

trigger:
- staging
- production

resources:
  pipelines:
  - pipeline: firstpipeline   # Name of the pipeline resource
    source: firstpipeline       # Name of the triggering pipeline
    trigger: 
      branches:
        include:
        - staging
        - production
variables:
  - name: isProduction
    value: $[eq(variables['Build.SourceBranch'], 'refs/heads/production')]
  - name: isStaging
    value: $[eq(variables['Build.SourceBranch'], 'refs/heads/staging')]

stages:
- stage: A
  jobs:
  - job: A1
    steps:
    - script: |
        echo "isProduction: $(isProduction)"
        echo "isStaging: $(isStaging)"
        echo "Build.SourceBranch $(Build.SourceBranch)"

So as a source you should use name of the pipeline not the yaml file.

You can find this here on github