Unable to login with web gui

I got openmediavault today for raspberry pi 3 Model B and got everything working except the web interface. Every time I try to login with the web interface with admin and "openmediavault" password I only get the "software Failure. Press left mouse button to continue. Incorrect username or password." I can connect to the server with ssh and sftp but the web interface just won't work. I have also tried to reset the password with omv-firstaid and inputted another password but that didn't work either. Glad if someone can help me with this.