That depends on how you entered the payments.  If you create the prior invoices, you will need to create the back customer payments and remove the entries that are there now.

Resolution for 'backlog invoices issue: 'How can you backlog invoices paid from before your QB subscription?' available: Yes.

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

For more information about resolving issues related to backlog invoices in Quickbooks/QBO or to get support for the issue 'How can you backlog invoices paid from before your QB subscription?', click the link below: