diff --git a/paymentsheet/src/main/java/com/stripe/android/paymentsheet/paymentdatacollection/ach/USBankAccountFormViewModel.kt b/paymentsheet/src/main/java/com/stripe/android/paymentsheet/paymentdatacollection/ach/USBankAccountFormViewModel.kt
index 508f210bcfd..dfd8aa73350 100644
--- a/paymentsheet/src/main/java/com/stripe/android/paymentsheet/paymentdatacollection/ach/USBankAccountFormViewModel.kt
+++ b/paymentsheet/src/main/java/com/stripe/android/paymentsheet/paymentdatacollection/ach/USBankAccountFormViewModel.kt
@@ -545,7 +545,8 @@ internal class USBankAccountFormViewModel @Inject internal constructor(
 
         return ElementsSessionContext.BillingDetails(
             name = name,
-            email = email,
+            // The createPaymentDetails endpoint does not accept lowercase email.
+            email = email?.lowercase(),
             phone = phone?.let { phoneController.getE164PhoneNumber(it) },
             address = address?.let {
                 ElementsSessionContext.BillingDetails.Address(