Make clients required payments in registration form

Several people are trying to register for my event. They get an error that says there is a problem with the client. PLEASE help me! I need to get everyone registered by today. What have I done wrong?

Can you please provide us with more details as to exactly was the Client error? 

I checked your form and I see it is using PayPal Checkout payment integration.

Was the error on the PayPal payment?

Please elaborate further on the issue and we will check again.

They can register but can’t pay.

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You may want to set the payment field *Required so that respondents will be required to use payment submission.