Generally, all messaging trouble is related to how contact information is stored within the goTenna App. Simply, if a user has setup their account using a random ID instead of a phone number, using their imported smartphone contact number will result in an inability to message. Confirm that you have the proper contact listed. Similarly, if your contact information for a user, within the goTenna App, does not reflect the proper country code, messaging will not work. You can try the following bellow tests to make sure you're set up to message properly.
Confirm the contact information is stored properly:
1) Open 'Contacts' in the goTenna app.
2) Scroll to the user you wish to establish a 1 to 1 chat with and tap on their name.
3) Once open, tap the info 'i' in the upper right hand corner of the screen.
4) Select 'Edit Contact'.
5) Confirm that the contact number has the proper country code in the number. For example, in the US, 1555-5555-555. Inputting the '1', or proper country code, will allow you to establish a 1 to 1 chat. Note, the format will look a little different than a standard phone number.
Try the Shout test:
1) Confirm both goTenna devices your testing have been successfully paired.
2) Send a shout. If the shout is successfully received, then both goTenna units have been set up properly.
3) From the shout message, press and hold the received message.
4) A menu will pop up, select 'Send Private Message'. This will open a 1 to 1 chat with the user.
5) Send a private message. This is the easiest way to start your 1 to 1 chat thread.
Because goTenna Mesh transmits on RF, the root cause of this issue is almost certainly the recipient's stored contact information. Likewise, range can effect message delivery; as you conduct these tests, first try at very close range and extend from there.