Activation by Email Sign-In is currently NOT supported on SnapGene version 8.0 or later for Linux.
If you have a SnapGene license that requires Email Sign-In and, you are running SnapGene 8.0 or later on a Linux operating system, then please contact our Customer Support team and request a legacy license key that will work on Linux (see the following article for supported Linux versions - What are the System & Hardware Requirements for SnapGene?).