@Alpesh Rabari It seems like the issue is related to the Azure DevOps release pipeline and the hosted agent, As suggested in Official document:
If your pipeline gets an agent but fails to complete, check the following common issues. If your issue doesn't seem to match one of these, see Get logs to diagnose problems.
Also, you may want to know that Azure DevOps is not supported on Microsoft Q&A. Please check this supported products list here.
The Azure DevOps team and community are active and answering questions on https://developercommunity.visualstudio.com/spaces/21/index.html suggest you post your question there and experts will guide you.
You can also ask for help here: https://stackoverflow.com/questions/tagged/azure-devops
Please "Accept as Answer" if it helped so it can help others in community looking for help on similar topics.