Why is my CIS return being rejected?

Thank you for visiting here in the Community, @sharon-ann-jay-h. I'm here to help and ensure you're able to submit CIS returns. 

Before we begin, please consider the following reasons for your return's rejection: 

1. In Account and Settings, the CIS credentials are incorrect.
2. All suppliers' references and CIS set up are incorrect.
3. Your credentials for the HMRC Government Gateway are invalid.

You need to make sure all mentioned information above is correct. You can log into the HMRC website to confirm your credentials.

If the issue persists, you can reach out to our contact support. They will also provide you with the necessary information regarding your concern. 

I've also attached some articles you can refer to for your future guidance and detailed steps in managing your CIS:

• CIS guide in QuickBooks Online
• How to unfile a CIS return in QuickBooks Online

Fill me in if you have other questions about submitting a CIS return. I'll be around to help you again. Keep safe and have a good one.