I am running Icinga with Classic UI, but an year ago I added the Icinga-web as well.
I have tested a couple of things with it and left it behind.
Now I want to access it, but I don`t remember what were the credentials.
Is there a way to reset the password or to create a new username and password for it?
Thank you in advance.
Depends how you've installed Icinga Web 1.x in the first place. The sources contain a make parameter to safely reset the root user's password.
https://docs.icinga.com/latest/en/icinga-web-scratch.html
If you are using Debian packages, you can reconfigure the package: