If you submit your email address once, you should no longer be prompted for it. However, there is a known issue that a domain user's manually submitted email address is overwritten when the user is rescanned. If your Lansweeper installation has a daily user scanning schedule, this explains why you keep getting prompted for your email address.
A fix is planned for a future release to prevent manually submitted email addresses from being overwritten. We don't have an estimated release date for this release yet though. If you would like to be added to our list of beta testers so you are notified of new updates prior to them being released to the general public, I recommend contacting support@lansweeper.com and providing a link to this forum topic.