There is a difference between the "Collected on sales" amount and Line 103 GST/HST collected/collectible in the Prepare return --> View summary. What could it be due to ?

Hi ybgssind-gmail-c,

I know how important it is to you to keep your sales tax records accurate. QuickBooks Online has a hearty sales tax module that's designed to be right on the money. If there's a discrepancy, I want to help you get to the bottom of it.

There are two things that you should check. The first is that your dates are matching, the report in the Sales Tax module will be set by remittance periods, and the Summary will be based on the dates specified. The other thing to check is what accounting method the Summary report was run in Cash or Accrual, and the Tax report will be calculated by your company's accounting method. Check out this article that explains How Cash and Accrual accounting affect sales tax.

If you've checked those settings and there were no red flags, the next step is troubleshooting your internet browser. You can so do through these simple steps: 

• Clear your browser cache if you're using a browser
• Try a browser if you're using the app
• Try a private browser window
• Try another browser type
• Make sure you're using a supported browser and system
• Reset your Internet or try on another computer or device

Check your reports between steps, and if the issue doesn't resolve itself, I recommend contacting a support agent for further troubleshooting through information specific to your company that shouldn't be shared in a public forum like the QuickBooks Community.

You can reach a support agent by one of these methods: 

Phone: Call us at 1-855-253-1536 from Monday to Friday between the hours of 9 AM and 8 PM EST.
Schedule a Callback or start a Chat: click (?)Help in the upper right > type and enter "Contact support" into the QB Assistant > click Contact Us > explain your situation > click Let's Talk > choose Get a callback or Start a Chat. 
Social Media: Facebook, Twitter, and Instagram.

I'm confident that this will be resolved in no time. You can always come back here if you have any other questions. Have an awesome weekend!