If it’s error 9999 it’s a known scripting error Intuit is working on. See:
Resolution for '1640087banking issue: 'Can’t log in to bank account' available: Yes.
The 1640087banking 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 1640087banking issue yourself by looking for a resolution described in the article. If it is a complex 1640087banking issue or you are unable to solve the issue, you may contact us by clicking here or by using other 1640087banking support options.
For more information about resolving issues related to 1640087banking in Quickbooks/QBO or to get support for the issue 'Can’t log in to bank account', click the link below: