I'm sorry, but the knowledge sources do not contain any information about current bugs or outages affecting Lookup Tables in Mixpanel. If you are unable to open a Lookup Table, it could be due to a temporary issue, permission restrictions, or other factors not documented in the provided sources.
If the problem persists, I recommend checking your user permissions (only Admins and Owners can manage Lookup Tables globally), ensuring your CSV and mapping are correct, and reaching out to Mixpanel support for further assistance. You can also try refreshing the page or using a different browser to rule out local issues. For more on permissions and managing Lookup Tables, see the documentation on Lookup Tables.