Hi, @Uniqaya. I'm happy to help you out with this!
Based on the screenshot you shared it looks like you'll need to update to the latest version of the payment integration you're using, or consider using a different payment gateway to accept payments going forward. Since Paytm is a third party payment gateway we won't have more information to share about this, but you can speak with them for more help. If you are considering using a different payment gateway, this page can help you find alternative options to use with Shopify in your region.
Please let me know if you have any questions!
Erin | Shopify - Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog