Board now needs at least 6V to send SMS?

Hello, When I first got this board I was able to send an SMS using only 5V plugged into Vin and GND plugged into GND (and supplying enough current). When I try to do that now I'm able to power the board but it doesn't send an SMS. But if I increase the voltage to 6V it can send the SMS. Interestingly though, if I plug it into my laptop's USB port or to an external power bank (output 5V at 2.4A max) it can send the SMS. Any ideas on why that would be the case?

Never mind, I was doing something wrong. For one, I wasn't supplying as much current as I actually needed even though I thought it was enough. I also saw another post on the forums discussing how the there's an issue with the Vin pin having too high of a voltage drop, which would explain the higher-than-normal voltage I needed to supply. I instead used the USB connector to supply the voltage, which doesn't seem to have this issue.