I just want to ask if somebody encounters error in generating a custom report.

Hello there, perezmareciel.

I'd love to help you fix that particular error when running a custom report in QuickBooks Online.

Can you share if you've got an error message? This helps me determine your issue and provide an accurate solution to your concern.

In the meantime, we can use a private browser or an incognito window upon logging in to your account to isolate this. This prevents your browser from storing additional cache files. Also, this mode is free from cache files that avoid storing internet data.

 We can follow the shortcut keys below.

• For Chrome, press and hold Ctrl +Shift +N.
• For Firefox, press and hold Ctrl + Shift + P.
• For Safari, press and hold Command + Shift + N.

If it works fine, we can clear the cache and temporary internet files to optimize the browser's performance: Clear cache and cookies to fix issues. Another way is to use compatible browsers with QuickBooks Online.

I've gathered a few articles for tips and information about managing QuickBooks reports. 

• Learn what reports are included in your QuickBooks Online subscription.
• Customise reports 
• Memorise reports 

Don't hesitate to add another post if you need further help. I'm always around to assist your with your QuickBooks reports. Stay safe, and have a good one.