You've probably landed here because you're on the signup page and have triggered this message...
What this means is that we have recognised the domain part of your email address (the part after the @ symbol) against an existing Timetastic account.
e.g. if you are trying to signup with firstname.lastname@example.org then it's the tesla.com we have identified as maybe already being a customer of Timetastic (for clarity - neither Elon nor Tesla are customers of Timetastic, I don't suspect that's his email address either, so I wouldn't bother trying it) 😁
Basically, the signup form is for companies that are new to Timetastic.
If, for example, you've started a new job and have been told that your employer uses Timetastic for booking time off, chances are this signup form is not for you. You'll need to ask a manager at work and they'll invite you to your employers account.
On the flip side, it might be genuine and you do need a separate account - in which case just ignore the message entirely, you can complete the rest of the signup form as normal.