Sidebar disappears in Banktivity 7.5.3, especially on macOS Big Sur. Workaround: Close Banktivity. Hold the Shift key while launching the app. Alternatively, try resizing your window to force a refresh.
Option 1: Forum/Reddit Post (Fixing Vanguard/Broken Downloads)
(e.g., Reddit, Twitter, a private forum)
Some users report that re-subscribing to Direct Access to force a token refresh, or simply exporting transactions via QFX from your bank and importing them manually, is the only way to get around the broken server-side connections.