Error 9999 was resolved recently. Did you try using the private window recently? We all had trouble connecting from Thanksgiving thru the weekend.
Resolution for 'connecting issue: 'My banks are not connecting and downloading transactions.' available: Yes.
The connecting issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the connecting issue yourself by looking for a resolution described in the article. If it is a complex connecting issue or you are unable to solve the issue, you may contact us by clicking here or by using other connecting support options.
For more information about resolving issues related to connecting in Quickbooks/QBO or to get support for the issue 'My banks are not connecting and downloading transactions.', click the link below: