Resource 'Microsoft.Web/sites/ under resource group 'myresgrp' was not found

[eliassal]

In item 9 it is mentioned
Select the Variables tab and add the following variables as detailed below.

appservice-name | Your appservice-name

it is greyed out, I am not able to understand what this variable should have? I tried the my of
Container Registory
the name of my
Repository

When I create a release I get

2020-07-03T18:17:54.0154275Z [command]/usr/bin/az account set --subscription f151ee3f-4725-460d-8e3b-82512dfda843
2020-07-03T18:17:54.8737754Z [command]/usr/bin/pwsh -NoLogo -NoProfile -NonInteractive -ExecutionPolicy Unrestricted -Command . '/home/vsts/work/_temp/azureclitaskscript1593800269234.ps1'
2020-07-03T18:17:58.0953285Z ResourceNotFound - The Resource 'Microsoft.Web/sites/sierac' under resource group 'IgniteLearningPath' was not found. For more details please go to https://aka.ms/ARMResourceNotFoundFix
2020-07-03T18:17:58.4543468Z ##[error]Script failed with exit code: 1
2020-07-03T18:17:58.4565142Z [command]/usr/bin/az account clear
2020-07-03T18:17:59.2981765Z ##[section]Finishing: Configure Container settings to App Service

Wjat should be the service name?
Thanks