If it will not complete a GPS lock inside, no matter how many times you try and with all places, you could try this:
Grab a small UPS (buy one if you don't have one), plug it in that in the parking lot, wait for it to make a lock then just take it inside the office and put it by your window and plug the UPS in. Keep the MB plugged in the UPS.
If you don't have one, you can buy a cheap one like this: https://www.amazon.com/dp/B004OR0V2C