Audio Output and Mic Broken?

My Axon 7 started malfunctioning three days ago. I went to use Google Assistant and noticed that the mic wasn't registering any noise. Confused, I made a call to a friend and realized that they couldn't hear me and I couldn't hear them. I then went to play music from the default app and YouTube, and neither worked.

I tried plugging in my phone to car speakers via aux, and there was no sound. In fact, there was no audible crackle that usually accompanies connecting a music player to speakers that are already on.

When I restarted the phone, the problem was still there. I then shut it down and powered it back on, and it worked for about a day. The problem has been reappearing about once a day.

Does this seem like a software issue, or is something wrong with hardware connections? Any ideas?

TL;DR Phone's mic input and audio output don't work until restart. (Using an aux cable doesn't work either, haven't tried Bluetooth).