Report a bug — reelpile

Or just write

A mail client, your words, no form:

What makes a report easy to fix

The link you pasted, if it was an import that failed. Most import problems belong to one platform, or one post.
What you saw: an empty card, a spinning one, a message, nothing at all.
Your macOS version and whether it is an Apple Silicon Mac.
The app version, from the foot of Settings.

None of this is required. A sentence is better than nothing, and a screenshot is better than a paragraph.

Before you write

The manual says what each feature does and, in chapter 18, what the app deliberately does not do. If something is on that list, it is not a bug and no report will change it today.

Something broken?