Azure pipeline does’t allow to git push throwing ‘GenericContribute’ permission is needed

If you get the following error in your build…

TF401027: You need the Git ‘GenericContribute’ permission to perform
this action. Details: identity

…then, to fix it:

1. Copy the guid part of the identity name from the error message
2. Go to the repository settings
3. Paste the guid into the permissions search box for user or group.
4. This will then display a “Project Collection Build Service (OrganisationName)”. Select that user
5. Set the permissions as stated in other answers.