Build failure for emersion-go-imap

[Ben Fiedler <debian@services.bfiedler.ch>]

Hi all,

The source build for the golang-github-emersion-go-imap package
fails with a timeout during testing [1]. As far as I can tell
something on the build server interferes with the package tests.
Locally the package build correctly using both git-buildpackage
and sbuild, I have no idea why the build server failed on that
build.

Can some help me understand what the problem is and fix it with me?

Thanks and best wishes,
Ben

[1]: 
https://buildd.debian.org/status/fetch.php?pkg=golang-github-emersion-go-imap&arch=all&ver=1.0.4-2&stamp=1587744949&raw=0