Grafana login issue

Hi Team,
Somebody can help.
I haven’t used my grafana for last 2 weeks and when iam trying to open it . it is throwing error invalid login and password. I have default username/password as admin/admin.

Grafana server ip got changed after the reboot of my machine but now when iam trying with the changed ip , i can able to see the login page but credentials are invalid.

kindly help me.

Kindly refer to the following solution provided by @torkel