I can replicate that problem, but would suggest maybe that function is not enabled in the demo (even if it appears apparently so). The fact you can go as far as creating a user and setting permissions to administer the forms suggests it should be possible. I also get the "you have no access to any forms" when logging in as the user I create in the demo (even with "full administration" permissions it only shows "you have no access to any forms").
I have no other answer other than to suggest you contact Appnitro with a "pre-sales" question and ask them that question - since they don't often frequently visit the forum here - https://www.machform.com/contact/
The demo only states the restrictions being, the email functionality is disabled, and it resets the database after six hours. The demo is V7 of MF, the current release is V10, I don't know if that makes a difference.