Not user friendly

After downloading I applied for a free trial. I initiated downloading a movie. The system asked for my iTunes passport and approved the purchase (?). Then it started downloading and suddenly moved me to a new window where I had to enter my email and create a password. I received an email where I confirmed the subscription. From that moment on nothing was working. I came back to the selected movie but couldnt do anything because the system informed me that Im logged out. I tried to log in with the newly established password but the information was showing me just an error. I tried the forgotten password option. A new window popped out but not progressing. I checked the wifi speed and it was fine. Everything else was running fast.
Im trashing this app

Eremik about STARZ, v3.3.1