Error
The name supplied already exists. : Another product or service is already using this name. Please use a different name.
Cause
QuickBooks Online only allows 1 unique product name. If the product name already exists, this error will be given.
Example
This could be because you have trailing spaces in your item IDs. QuickBooks will remove the trailing space, while CW keeps it. So when we create it, QuickBooks changes it from "CCTV Level 2-Onsite | Maintenance " to "CCTV Level 2-Onsite | Maintenance". When we look for "CCTV Level 2-Onsite | Maintenance " we don't find it, because only "CCTV Level 2-Onsite | Maintenance" exists, so we try to create it again.
ConnectWise PSA: "CCTV Level 2-Onsite | Maintenance "
QuickBooks Online: "CCTV Level 2-Onsite | Maintenance"
ConnectWise PSA will treat those as two separate products (and let you have both), QuickBooks will delete the spaces from the end of the first one and treat them both as the same product. In this example, you can resolve the issue by removing the trailing space in ConnectWise PSA.
Resolution
1. Verify the Product Name in ConnectWise PSA does not have any leading or trailing spaces
2. If the product already exists in QuickBooks Online, Update the name by Copying the product ID Field from ConnectWise PSA and paste it directly into QuickBooks Online Name Field.
Please review the following articles to resolve the issue.