iTunes Connect - Is your app designed to use cryptography?

If you are using just HTTPS then there is no need to select this option. You can set it as NO. You have to set it to Yes only if you use custom cryptography in your code to encrypt or decrypt data. But if its just https calls then you can set this to No.

You can select NO as using HTTPS is now exempt from the Exporter Registration and Reporting (ERN) as of late September, 2016: https://stackoverflow.com/a/40919650/4976373

1. You must answer YES that the app uses encryption.
2. Using Test Flight you many have testers in foreign countries and thus possibly exporting cryptography.

You state that "users can make friends, chat" and this is what the requirement its about.

This is generally stupid but required by the U.S. government.

You will need to figure that out for yourself, consult BIS website or get a knowledgable lawyer/cryptographic domain expert.
Also see BIS encryption flowchart 1 and flowchart 2