Error on Paypal payment

=> Hello, we are facing this error on our checkout page, “UNPROCESSABLE_ENTITY - Should equal sum of (unit_amount * quantity) across all items for a given purchase_unit“
– https://prnt.sc/_ziqlrNdpOAl

=> Here is error log.

2022-12-19T06:07:12+00:00 DEBUG <------------------- WebToffee PayPal Express Payment ( Create Order API ) ------------------->
{
"intent": "CAPTURE",
"application_context": {
"brand_name": "Pure Invitation Wedding Invites",
"locale": "en-GB",
"landing_page": "BILLING",
"shipping_preference": "GET_FROM_FILE",
"user_action": "PAY_NOW",
"return_url": "https:\/\/wordpress-281395-2623766.cloudwaysapps.com\/wc-api\/Eh_PayPal_Express_Payment\/?c=order_details&p=https:\/\/wordpress-281395-2623766.cloudwaysapps.com\/checkout\/&intent=CAPTURE",
"cancel_url": "https:\/\/wordpress-281395-2623766.cloudwaysapps.com\/checkout\/?cancel_express_checkout=cancel"
},
"purchase_units": [
{
"items": [
{
"name": "Lottie Wedding Invitation - Greens x 21",
"description": "",
"quantity": 21,
"unit_amount": {
"currency_code": "GBP",
"value": 3.67
}
},
{
"name": "Extra line item",
"description": "",
"quantity": 1,
"unit_amount": {
"currency_code": "GBP",
"value": 0.07
}
}
],
"amount": {
"currency_code": "GBP",
"value": 99.9,
"breakdown": {
"item_total": {
"currency_code": "GBP",
"value": 77
},
"shipping": {
"currency_code": "GBP",
"value": 6.25
},
"tax_total": {
"currency_code": "GBP",
"value": 16.65
},
"shipping_discount": {
"currency_code": "GBP",
"value": 0
},
"discount": {
"currency_code": "GBP",
"value": 0
},
"handling": {
"currency_code": "GBP",
"value": 0
}
}
},
"shipping": {
"name": {
"full_name": "Avinash Patel"
},
"address": {
"address_line_1": "test",
"address_line_2": "test street",
"admin_area_2": "test",
"admin_area_1": "oldham",
"postal_code": "M15 4UY",
"country_code": "GB"
}
}
}
]
}
2022-12-19T06:07:13+00:00 DEBUG <------------------- WebToffee PayPal Express Payment ( Response on Create Order API ) ------------------->
{
"name": "UNPROCESSABLE_ENTITY",
"details": [
{
"field": "\/purchase_units\/@reference_id=='default'\/amount\/breakdown\/item_total\/value",
"value": "77",
"issue": "ITEM_TOTAL_MISMATCH",
"description": "Should equal sum of (unit_amount * quantity) across all items for a given purchase_unit"
}
],
"message": "The requested action could not be performed, semantically incorrect, or failed business validation.",
"debug_id": "a475c6b34752",
"links": [
{
"href": "https:\/\/developer.paypal.com\/docs\/api\/orders\/v2\/#error-ITEM_TOTAL_MISMATCH",
"rel": "information_link",
"method": "GET"
}
]
}

=> Note: We are using custom method to add product into cart, with custom quantity.

=> Website Logins:
https://privnote.com/CIjdpN2V#4wWoNu1mm

=> Product page: (Click on personalize your design button, and add more then 20 quantity product into cart)
– https://wordpress-281395-2623766.cloudwaysapps.com/shop-by-colour/green-wedding-invitations/lottie-wedding-invitation-greens/

The page I need help with: [log in to see the link]