Try running repair for the SolarWinds Netflow traffic analyzer found on your Orion server's control panel.
Complete it and let the Configuration Wizard complete
As janene16 suggested, the first thing to do would be to run the SolarWinds Configuration Wizard, and check the boxes to repair the website, services and database. Whilst it could be an issue solely with the database, repairing all three will ensure that any links are also restored.
Before doing so, backup your database to a separate location (i,e, don't overwrite any existing backup sets), as whilst the functionality of your system is not as it should be, it's better to be safe than sorry if the repair makes things worse....
Hopefully, that will sort your issue out! Do let us know how you get on
EDIT: One other thing, if you have any customisations applied to your web interface (custom logos, colours or login text etc) make sure you have this documented, as you may need to re-apply your customisations once the website has been repaired.