I’ve never managed to get the snagit “convert to animated gif” feature to work well for me.
When I want to convert mp4 to animated gif I tend to use Camtasia. But for short adhoc, “I’m in a hurry” conversions then I have found that the free online ezgif site works well - using the Video to Gif feature.
I often use this to convert small videos to animated gif for uploading to social media and especially Twitter.
Snagit makes it easy to create very small videos. I define a square region for Instagram, and use a rectangle for Twitter. Since the videos I convert to animated gif are very short (6 - 10 seconds) I usually record it twice with the different region sizes.
Then upload the .mp4 to ezgif and download the animated gif ready for releasing via buffer.