Once the invoice has been emailed to the customer when they go to click to pay on the link it shows an error. Why does this happen?

Hey there, tpmobilerepair-g!

Thanks for reaching out here in QuickBooks Online. Let's tackle that error message in your customer's invoices together and get it sorted out.

May I know what error message your customer receives when clicking the link? For us, to determine what happened.

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Microsoft Edge: Ctrl + Shift + P
• Safari: Command + Shift + N

For references, to help your customers if they can't pay for an invoice you sent them, check out this article: What to do if your customers can't pay their invoices online.

Additionally, you can visit these articles to learn more insights and information on the new invoice layout and other processes in managing invoices using QuickBooks Online: 

• See what’s new with estimates and invoices in QuickBooks Online
• Convert an estimate into an invoice in QuickBooks Online

If you need assistance and other concerns with customer payment transactions in QuickBooks Online, feel free to leave a comment below. Take care.

“400 Bad Request”.

Thanks for reaching back and providing the specific error, tpmobilerepair.

The 400 - Bad Request occurs when the server is unable to process the request being sent due to an issue that is perceived by the server (corrupted). The problem is on the website itself, and the common resolution is to clear your browser's cookies and cache.

Thus, I suggest letting your customer perform the basic troubleshooting steps shared by my colleague above. They can also disable browser extensions as they can interfere with requests.

If they already did but the error persists, it's best to contact our Phone Support team for further investigation. They have the necessary tools to securely look at your account and determine the main cause of this.

Here's how you can connect with them:

1. Go to the Help icon in the top right-hand corner.
2. Select Search, then press the Contact Us button.
3. Enter your question in the box and hit Continue.
4. Choose the best way you'll want to reach out to us.

Please know that they can accommodate you Mondays to Fridays from 6 AM to 6 PM PT and Saturdays from 6 AM to 3 PM PT.

Once your customer successfully paid their invoice, you can record the payment in QuickBooks Online.

If there's anything else you need help with aside from managing invoices in QuickBooks, let me know by adding a comment below. I'll be around to offer further help.