I’m trying to send an invoice. The app keeps saying invoice sent but it’s not sending? Not had this trouble before....

Hello Scott-hickey7-gm, 

Welcome to the Community page, 

Can you try clearing the app data and seeing if that resolves your issue you are having.  

Clear app data-

• in Quickbooks Online app:
• Android: From: button, select settings, then select Refresh Data, and then choose Yes. 
• In your device settings:
• Andriod: settings>apps (varies by device)>Quickbooks app from the list>storage>clear date 

IOS: from the MENU ☰, select Help & Feedback, click Refresh data, and then select Refresh

iOS: from your device's settings, select General iPhone storage and choose an app that's taking up a lot of space. Then click the Offload app 

If you still have issues after trying them steps then let us know.