movies freeze when using plex/roku

I have had plex for several years now and it was working fine up to a couple monthe ago. I have windows 10, am using roku 4, and I have my movies on an external hard drive connected to my computer.

I started noticing a movie i was watching would freeze and act like it is reloading or buffering but it would never restart. I would hit the back arrow on the roku remote, it would ask me if I wanted to restart or pick up where I left off. I would chose where I left off and hit the Ok button.

Movie would start where I left off. When this problem began, it would do it a couple times during a movie. Now it repeats this sequence about every 10 min, and it did get progressively worse. Thought it was my external hard drives that had all the movies so I bought a new HD and transfered all movies off of three drives to the new one. No change.

If I watch a movie on my computer through plex, I have no issue. Also, if I go to plex through roku and watch a movie in one of my friends library, no issue. Its only when I am watching a movie in my own library through plex that I have the issue. Also, if I watch netflix, or amazon video through roku, there is no issue. I hope all of this is making sense to someone out there

Moderator: Edited for readability