Let's get the issue resolved by doing troubleshooting steps. So you're able to use the GSTR3B report in QuickBooks Online as soon as possible. First, try logging in to a different private window to check if it's a cache issue or not.
Use these keyboard shortcuts:
Safari: Command + Shift + N
Mozilla Firefox: CTRL + Shift + P
Google Chrome: CTRL + Shift + N
Internet Explorer: CTRL + Shift + P
Once logged in, go back to the Reports page and check if you can successfully download the report. If it works, clear the cache of your regular browser to speeds up the web browsing experience. Using another compatible browser is a good alternative too.
If the issue persists, I'd suggest manually updating your Adobe Reader for stability improvements. Let me guide you how:
For Windows:
Launch the Adobe Reader, then click the Help button.
If you received this error, Something went wrong. We are working on it when accessing the report, I'd suggest calling our Customer Care Team. They can add your account as one of the affected users for this reported issue.
Here's how to contact:
Go to the Help menu, then choose Contact Us.
Type your concern in the description field and hit Let's Talk.
Click Chat, then complete the required information.
4. Tap Submit request.
To ensure we address your concern promptly, our QuickBooks Support is available Monday to Friday, around 9:30 AM- 6 PM, IST.