Luckily you aren't the only one to face this issue. This happens due to link failure with Big Bazaar main server. Bokaro although is a planned city but doesn't have a internet backbone installed unlike other cities like Jamshedpur, Purulia, Asansol. You will often find call drops, data problems there. Sadly BB's earning in Bokaro isn't great compared to its neighbors and thus gives less priority to these problems. If you use Jio in Bokaro than you will be considered the most unluckiest person there. Hope you got your answer!