It’s a script error. ¬†You must report it to QuickBooks.

See below.

https://community.intuit.com/questions/1640087-banking-error-9999-from-wells-fargo-this-has-been-goi…

Resolution for 'again giving issue: 'My bank is once again giving a 9999 error. Can you fix it?' available: Yes.

The again giving 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 again giving issue yourself by looking for a resolution described in the article. If it is a complex again giving issue or you are unable to solve the issue, you may contact us by clicking here or by using other again giving support options.

For more information about resolving issues related to again giving in Quickbooks/QBO or to get support for the issue 'My bank is once again giving a 9999 error. Can you fix it?', click the link below: