Urgent: All of a sudden, customers are getting error 406 when attempting to pay.

Urgent: All of a sudden, customers are getting this error when attempting to pay:

Client error response [status code] 406 [reason phrase] Not Acceptable [url] https://api.globalgatewaye4.firstdata.com/transaction/v14

We are using the Payeezy Pay Option.

Please advise.

Could you try with Stripe SCA and see how it goes?