State your name clearly so the caller knows they have the right number. 3 of the messages I heard last month were missing his/her name.
Typically when I’ve used ngrok on long term projects, I’ve paid the subscription fee which lets you choose a subdomain for it so that it stays the same. For something like this, the fee might be worth it to save you the hassle each time 🙂

7. Leaving Recorded Messages on Voicemail: One of the most valuable features of sending recorded phone messages is that the technology knows when a person picks up the phone, versus voicemail.
I have a confession to make: I haven’t recorded a new voicemail greeting since 2014. In the past four years, I (hopefully) have become more articulate, poised, and self-assured. But hear my voicemail recording, and you’d think I was still new to the work world, a little unsure of myself — and probably not an authority. Obviously I need toupdate it. And if you haven’t changed your voicemail greeting in over a year, you’re likely in the same boat. After all, a professional voicemail recording boosts your credibility, makes you seem more competent, and encourages whoever’s listening to it to continue the relationship. A relatively unprofessional one — like mine, for instance — does the opposite: It encourages prospects, recruiters, and potential connections to run in the other direction. With that in mind, I’ve written 18 unique voicemail greetings for every situation. Pick your favorite, practice a few times, then record your new voicemail.