Check sync status
If you just connected, import may still be running. Recent mail shows first, then older threads. Give it a bit—sync runs in the background.
Reconnect permissions
If you revoked Gmail or Outlook access, reconnect from Settings. After reconnecting, new mail will resume and older threads continue importing.
Bulk actions
Large bulk actions in Gmail or Outlook (thousands of threads at once) can temporarily slow imports. Prefer smaller batches or run overnight.