TitozzTitozz same issue with mine customer app :
But customer app has an issue with the Paytm gateway where customers have to enter UPI id manually Because not redirected to the UPI app Google pay and phone pay.
If customers order from the site (browser) able to pay via Paytm UPI without any issue.
Reported issue to Paytm, response is there is no issue.
That's why we disable Paytm and use Razorpay.