My Samsung S5 plex does not play a movie over 1 min

Hi All,
I have installed Plex on My Samsung S5 and I connected with my Google Account.
I can see my Plex server and all the movies inside it.
But when I try to play - It stopped after a minute.
I thought Plex for Android is Free - the same as all the others, Am I right?

The App is Not working on my Samsung S5 Smartphone and I would be happy to know if I need to install a different App on my phone?
Please assist.

Thanks
Arye

Plex for android is not free.

You need a plex pass for the applications to be free, or you need to pay the one time unlock fee.