@Staffan Willén There are a few things that can cause this, but the most obvious is to make sure that you are added as a classic administrator to the subscription. Even if you are listed as an owner for the subscription, you might need to add yourself as a classic administrator.
If that does not work, see if you can see the resource using azure classic powershell. If the resource does not show up, it is likely in a different subscription / resource group.
If you need additional help, please let me know.