I’m having an issue with no sound when calls are answered. Neither party can hear the other although the call is connected. I found a similar thread with no resolutuon.
Sim card is Mint. The card works in my Samsung phone, and a USCellular card (also TMo) works in the Brax3. I also received a call from Mint when setting up the card. APN looks ok. Phone has permissions. Any thoughts? Please explain like I’m 4 as my phone tech knowledge is extremely limited. Thanks.
Reboot the phone and try some other phone apps from F-droid , someone had a similar problem with the speaker and it was fixed for the native app after using another app.
Downloading a different phone app worked. Thanks!
Which app did you download ?
Fossify phone.
Here are some extra words to make the post long enough. 
Thank you, just searched fdroid and couldn’t figure out which would work.
Note: I did see the Fossify offering and currently use their calendar and messages so was a bit concerned about creating another “monopoly “. Any concerns there?
Monopoly for something open means that it’s a good product but anyway you can spin-off it anytime like with Firefox.
Good choice! (IMO) 
On related note if you are new to BraX3 see also my thread here that might help with suggested apps to get started with if you haven’t already:
I can especially recommend using most of the Fossify suite - Phone, Messenger, Contacts, Files & Gallery (Camera not so much).
(I primarily use the Fossify Files app, rather than the default Files app included in iodéOS):
Also if you ever have issues saving attachments from messages, etc, see this thread:
P.S. Recommend the Save Locally app as a secondary solution if you ever have issues long term with saving attachments.