You cannot change your e-mail address yourself: ask for a correction in your account, under Settings › Your data, or write to us from your current address.
Your e-mail address is how you sign in, and where we send password links and the confirmation of your purchases. Neither the app nor the website has a way to change it.
To have it corrected, ask in your account on licento.com, under Settings › Your data, and we write to your current address to ask which address you want instead. Or write to us from the address on your account. We act only on a request made from your account or sent from that address, so that your account never goes to someone else. We reply within one month.
To change your password instead, use «Change password» in your account's settings: we send a link to your e-mail address.