Weird behavior with my phone's wifi reception in my office

My iPhone will connect to my office's wifi network without any issues, however, the actual internet access over the wifi signal is on and off. Simply turning off and on my phone's wifi antenna will get the internet working again, but it will only work for 15 minutes or so before it goes back off. I don't know if this is something to do with my office's wifi or my phone (iPhone 7+).

My office has two networks, one for employees and one for guest. I've tried using the guest network too, but it still does the same thing. We had a consultant in the office last week, and he was connected to our guest network, and he was experiencing the same issue with his MacBook.