So this is the kind of anxiety where you wind yourself up before anything goes wrong. You dread the meeting, speaking up, presenting, dealing with the person who you might find intimidating or difficult. Here are a couple of tips that can help:

1. Meet in person. You’ll give the people in the meeting the advantage of eye contact, body language….non-verbal messages which can be critical for accurate interpretation of what’s being said. This is especially important if you don’t know the person well.
2. Figure out what you’re going to say before the meeting. When I presented decks, I would write the key points I wanted to make on each page. Yup, I basically wrote my script. And I practiced.  It’s VERY hard to be articulate and succinct off the cuff. Add adrenaline, and you can go blank.  So write it down, and practice. It’ll become muscle memory.
3. Get the right mindset going in: it’s easy to think that the other person is judging you, that your competency is in question because they’re probing. Don’t go down that dark and twisty path. Chances are, you’re there because you’re the Sherpa, and they’re about to climb Mount Everest. You are there to help them…there’s nothing to prove. If you had no value, they wouldn’t show up to the meeting.
4. Do your homework: if you want opportunities to speak up more in meetings, read the presentation ahead of time. Write down comments that you’d like to make at the presentation, or questions you might want to ask. Overkill? You’ll probably be the only one in the room who is prepared.
5. Don’t wing it if you don’t know: if you get a question that you don’t know the answer, say “That’s a great question. Let me check that and get back to you.” And follow up. No need to be flustered.

The more you do the above, the easier it gets.