Jetpack subscriptions not accepting potential subscribers

People who want to subscribe to my blog can’t seem to do so. The Jetpack subscriptions was working for a few weeks for most people. Now I have more potential subscribers who can’t subscribe. (Some have tried 3 or 4 times.) I reminded them to check for the confirm email and asked them to check their spam box. Still they can’t subscribe. My blog is https://nickichenwrites.com/. What can I do?

https://www.ads-software.com/plugins/jetpack/