I have just setup Azure DevOps Server 2019 (on-premises) and create a project then up source code to Azure Repos.
But when I create new build pipeline from Web Interface, after select source, I cannot select to create pipeline setting on "Configure your pipeline"
Page because it was blank.
Is there any solution for this situation?
P.s: my source code run on .Net framework
According to your description, seems you were stuck with below step:
There should be options as above, you just need to select one of it. Then system will auto create an azure-pipelines.yml
file.
If it's totally blank, suggest you give a try with another browser first such as Chrome/Firefox/Edge, better with private mode enabled.
Besides, instead of creating YAML build pipeline. You could also give a try if you are able to create classic editor.
In this way, you should be able to create build pipeline through UI.