open the chart of accounts, use the gear at the top of the listing and select show inactive,find the account and make it active again

Resolution for 'active again issue: 'how do I undelete an item in my chart of accounts' available: Yes.

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

For more information about resolving issues related to active again in Quickbooks/QBO or to get support for the issue 'how do I undelete an item in my chart of accounts', click the link below: