Your connection to the server is not fast enough

I have been running Plex on my Synology DS918+ for approx. 8 months with NO issues.

Suddenly when I stream my video files (MP$ - 480p) I am receiving the following error- “Your connection to the server is not fast enough to stream this video. Check your Network”.

I am receiving this error on ALL of my client devices (smart TV, Fire TV, etc). However, I am able to stream other services with NO issues on the same devices (NetFlix, Amazon, Video on demand).

I have made no recent changes to my wireless network.

I can also stream the same video files on my NAS with my smart TV using the built-in DNLA player with no issues.

Considering the facts above I would think this indicates a problem with the Plex server.

Any help or alternative viewpoints would be appreciated. Thank you.

Same issue - no change to HW or Network. Content plays fine on the web player, but streaming to FireTV and FireStick I only get the first few seconds of any content before the “Connection not fast enough” error. I have not had this error in the last 12m at all with any content.
Server is running on Windows 10, v1.120.0.4829
FireTV is running v6.14.1.3753

Have tried a selection of content from 576p to 1080p - still get the error. FireTV and Plex Server are on the same wired 1Gb LAN.

I have no problem streaming to a web client on a Windows laptop over Wifi.

Interestingly - if I change the settings on the client on my FireTV to force PMS to transcode it works fine. Its only when the overlay is showing as “DirectPlay” that I get the error. In the old client (way back when) there was a setting which allowed me to disable DirectPlay this is not available anymore it seems. For now my work around is to set maximum playback on the FireTV client to 720p - this forces a transcode and everything plays back nicely. As a side benefit - my PMS now heats up my office, so I can turn the heating off!