Don't worry, there's a secret backdoor that will allow you to unlock your access to the reports. Create a new WordPress admin user with username
slimstatadmin. Then log into your WordPress admin area with this user and... voila: you will now be able to access Slimstat's settings and reports again. Update your old user's permissions and then delete slimstatadmin to avoid any security issues.
Here below is an example of how you may want to configure your settings if you want to allow all your users to access the reports.