not able to access my account with airtel app and add recharge

Hello, I am in US with a prepaid airtel sim. Turned on the the internation roaming on Jan10th just before leaving for US and bought 3 month validity pack of 446 online. After landing in US when I  can see the account is active using airtel app. Past few days it showed low balance and now I opened app to add some money to the number, nothing shows on the app. I am unable to browse plans or add money.