How to resolve "No hosted parallelism has been purchased or granted" in free tier?

I've just started with Azure DevOps pipelines and just created a very simple pipeline with a Maven task. For now I don't care for parallelism and I'm not sure in which way I've added it to my pipeline. Is there any way to use the Maven task on the free tier without parallelism?

This is my pipeline:

 trigger:
 - master
    
 pool:
   vmImage: ubuntu-latest
    
 steps:
 - task: Maven@3

My thought was that tasks are always parallel? Other than that I cannot see where's the parallel step.

First - tasks are always executed sequentially. And 1 sequential pipeline is documented as "1 parallel agent", yes naming could be better. Due to the changes laid out below new accounts now get zero parallel agents, and a manual request must be made to get the previous default of 1 parallel pipeline and the free build minutes.

See this:

We have temporarily disabled the free grant of parallel jobs for public projects and for certain private projects in new organizations. However, you can request this grant by submitting a request. Existing organizations and projects are not affected. Please note that it takes us 2-3 business days to respond to your free tier requests.

More background information on why these limitations are in play:

• Change in Azure Pipelines Grant for Private Projects
• Change in Azure Pipelines Grant for Public Projects
• Changes to Azure Pipelines free grants

TLDR; People were using automation to spin up 1000's of Azure DevOps organizations, adding a pipeline and using the service to send spam, mine bitcoin or for other nefarious purposes. The fact that they could do so free, quick and without any human intervention was a burden on the team. Automatic detection of nefarious behavior proved hard and turned into an endless cat-and-mouse game. The manual step a necessary evil that has put a stop to this abuse and is in no way meant as a step towards further monetization of the service. It's actually to ensure a free tier remains something that can be offered to real peopjle like you and me,

This is absurd. 'Free-tier' is not entirely free unless you request again!

Best Option: Use self-hosted pool. It can be your laptop where you would like to run tests.

MS azure doc here

and use above pool in YAML file

pool: MyPool

Alternatively

Request access to MS:

Folks, you can request here. Typically it get approved in a day or two.

##[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