Nice progress! New email from Tutanota still goes to the Gmail spam folder for me even though past emails were marked not spam". It might take some time and lots of good email to the big email services for the issue to clear itself up.
That was an odd and quick bounce. @Tutanota I'm curious if you needed to built any bot detection into your webmail yet to help prevent automated spamming?
Yes, we're also glad it worked out quickly. We took immediate steps once we've noticed the abuse. We did implement bot detection against spamming as well. Probably the most effective method was limiting sent emails to 100 per day so that Tutanota is just not attractive to spammers anymore. Also we are glad that none of our regular users complain about the limitation. Now we are working hard on releasing premium features so that heavy users can upgrade.