Unfortunately a new generation of the funnel is gaining popularity in the last years: "sign up with your work e-mail", where Gmail etc. are rejected. So you nee

Unfortunately a new generation of the funnel is gaining popularity in the last years: "sign up with your work e-mail", where Gmail etc. are rejected. So you need to make some effort to find a free e-mail provider that is not on their banned domains list. Unless of course you actually don't mind spam and pseudospam ("Hi it's Mike from MyStartup. Just checking up as you haven't replied to my previous message...") in your work mailbox.