When I ran my pipelines, I get this error:

##[error]No hosted parallelism has been purchased or granted. To request a free parallelism grant, please fill out the following form https://aka.ms/azpipelines-parallelism-request

Solution:

Go to Project settings > Parallel jobs > Click Change > Self-Hosted CI/CD > Change to 1 
    
Visit parallel jobs for full details on free pipelines and public concurrency