No service for calls or texts indoors

I have an LG stylo that was a t mobile phone. Bought the Sim for t mobile phones and transferred to straight talk.. Phone works great, but I have no service inside. And I can't get the wifi calling to work. As soon as I step outside I get hit with voice mail notifications and texts. What can I do to fix this? Does straighttalk supply a cell signal booster I can use inside?