GitHub OAuth integration for Grafana - github

Question

I'm trying to have GitHub OAuth integration for Grafana and I am following this document:
https://grafana.com/docs/grafana/latest/auth/github/
Accordingly, I've configured my values.yaml file with similar configuration as shown below:
## grafana Authentication can be enabled with the following values on grafana.ini
server:
# The full public facing url you use in browser, used for redirects and emails
root_url: https://grafana.example.space
# https://grafana.com/docs/grafana/latest/auth/github/#enable-github-in-grafana
auth.github:
enabled: true
allow_sign_up: true
scopes: user:email,read:org
auth_url: https://github.com/login/oauth/authorize
token_url: https://github.com/login/oauth/access_token
api_url: https://api.github.com/user
team_ids: 259420
allowed_organizations: Orgs
client_id: 123456
client_secret: 123456
My Github OAuth app URLs are configured as shown below:
Homepage URL:
https://grafana.example.space
Authorization callback URL:
https://grafana.example.space/login/github
But, while I try to login using the Github authentication, I can see an error as below:
t=2022-01-02T12:33:03+0000 lvl=eror msg="Failed to look up user based on cookie" logger=context error="user token not found"
t=2022-01-02T12:33:03+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/live/ws status=401 remote_addr=49.206.14.15 time_ms=0 size=32 referer=
Can someone please help me as to where am I missing out here?