i am facing below issue in git based wiki updater task - azure-devops

Question

I created Authentication token as well all permission for user which running pipeline is defined

Answer 1

If you checked Run with Build Agent Credentials as Authentication in the task. And the build account {ProjectName} build service ({OrganizationName}) was granted Read and Contribute permission in the Wiki Security page.
But you still encounter above error. It's probably because you have IIS Basic Authentication turned on in the Azure DevOps Server machine. When IIS Basic Authentication is enabled on your windows machine, it prevents you from using personal access tokens (PATs) as an authentication mechanism. See here.
We recommend you keep IIS Basic Authentication turned off at all times when using Azure DevOps Server. Only if necessary should you enable IIS Basic Authentication. When IIS Basic Authentication is enabled on your windows machine, it prevents you from using personal access tokens (PATs) as an authentication mechanism.
As workaround to this, you can add an extra header which includes a base 64 encoding of "user:PAT" to the Git requests when IIS Basic Authentication is enabled:
So you can run the pure git commands in a powershell task to update your wiki repo, instead of uisng the git based wiki updater task. See below example scripts in the powershell task (yaml format):
steps:
- powershell: |
git config --global user.email "your#eamil.com"
git config --global user.name "name"
$MyPat = "$(system.accesstoken)"
$B64Pat = [Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes(":$MyPat"))
#clone the wiki repo
git -c http.extraHeader="Authorization: Basic $B64Pat" clone https://server/collection/_git/Document.wiki -q
cd Document.wiki
#add a new file
echo echo "some-text" > addnew.md
git add .
git commit -m message
#push to wiki repo
git -c http.extraHeader="Authorization: Basic $B64Pat" push https://server/collection/_git/Document.wiki -q
displayName: 'update wiki'
Check here for more information.
In order to use the Build Agent OAuth token $(system.accesstoken) in above script. You need click the Agent job 1 and Check the option Allow scripts to access the OAuth token