Setting up sub users

I have set up sub users for our account.  When I set it up the user receives an email advising which folders are shared but nothing about logging in.  We tried using their email address and trying to reset password but it says they don't exist and tries to create a guest login to the system. 

When I set them up it says an invitation was sent. I deleted them and tried again in case I had something wrong, but can't see any extra steps or anything else to do. 

How do they get a password and log in?

Thanks 

I have solved it - it looks like that user had created an account a long time ago.  We created an account for them again and here was an old form in there.  Shared to them again and all OK. 

Thanks 

Glad to know you figured it out, if you have another question, please open a new thread, we will be glad to assist you.