I got one error: Conversion failed. A required codec could not be found or failed to install.

nas:ds3615xs
plex version:Plex Media Server v1.12.3.4973-215c28d86

when i went to play any movie,i got the same err: Conversion failed. A required codec could not be found or failed to install.

i had deleted pms,and deleted all folder about pms,and reinstalled ,just added one movie ,and got the same err。

logs:
May 06, 2018 19:13:20.873 [0xefe23b70] DEBUG - MDE: Cold: Direct Play is disabled
May 06, 2018 19:13:20.873 [0xe83ffb70] DEBUG - MDE: Cold: Direct Play is disabled
May 06, 2018 19:13:20.873 [0xe83ffb70] DEBUG - MDE: Cold: media must be transcoded in order to use the dash protocol
May 06, 2018 19:13:20.873 [0xefe23b70] DEBUG - MDE: Cold: media must be transcoded in order to use the dash protocol
May 06, 2018 19:13:20.873 [0xe83ffb70] DEBUG - MDE: Cold: no direct play video profile exists for http/mp4/h264
May 06, 2018 19:13:20.873 [0xefe23b70] DEBUG - MDE: Cold: no direct play video profile exists for http/mp4/h264
May 06, 2018 19:13:20.873 [0xe83ffb70] DEBUG - MDE: Cold: no direct play video profile exists for http/mp4/h264/aac
May 06, 2018 19:13:20.873 [0xefe23b70] DEBUG - MDE: Cold: no direct play video profile exists for http/mp4/h264/aac
May 06, 2018 19:13:20.873 [0xe83ffb70] DEBUG - MDE: Cold: selected media 0 / 1
May 06, 2018 19:13:20.873 [0xefe23b70] DEBUG - MDE: Cold: selected media 0 / 1
May 06, 2018 19:13:20.873 [0xe83ffb70] DEBUG - Streaming Resource: Added session 0xe9e13194:nqni3pvso9q1shkfx5b9hmjg
May 06, 2018 19:13:20.873 [0xe83ffb70] DEBUG - Streaming Resource: Reached Decision id=1 codes=(General=1001,Direct play not available; Conversion OK. Direct Play=3000,App cannot direct play this item. Direct play is disabled. Transcode=1001,Direct play not available; Conversion OK.) media=(id=1 part=(id=1 decision=transcode container=mp4 protocol=dash streams=(Video=(id=1 decision=copy width=1920 height=1080) Audio=(id=2 decision=copy channels=2 rate=48000))))
May 06, 2018 19:13:20.873 [0xefe23b70] DEBUG - Streaming Resource: Reached Decision id=1 codes=(General=1001,Direct play not available; Conversion OK. Direct Play=3000,App cannot direct play this item. Direct play is disabled. Transcode=1001,Direct play not available; Conversion OK.) media=(id=1 part=(id=1 decision=transcode container=mp4 protocol=dash streams=(Video=(id=1 decision=copy width=1920 height=1080) Audio=(id=2 decision=copy channels=2 rate=48000))))
May 06, 2018 19:13:20.873 [0xe83ffb70] DEBUG - Found session GUID of tv7lx5n5gd9gb4jr2jo5ck9a in session start.
May 06, 2018 19:13:20.873 [0xe83ffb70] DEBUG - Cleaning directory for session tv7lx5n5gd9gb4jr2jo5ck9a ()
May 06, 2018 19:13:20.874 [0xe83ffb70] DEBUG - Starting a transcode session tv7lx5n5gd9gb4jr2jo5ck9a at offset -1.0 (state=3)
May 06, 2018 19:13:20.874 [0xf03ffb70] DEBUG - Completed: [192.168.1.237:55891] 200 GET /video/:/transcode/universal/decision?hasMDE=1&path=%2Flibrary%2Fmetadata%2F1&mediaIndex=0&partIndex=0&protocol=dash&fastSeek=1&directPlay=0&directStream=1&subtitleSize=100&audioBoost=100&location=lan&addDebugOverlay=0&autoAdjustQuality=0&directStreamAudio=1&mediaBufferSize=102400&session=tv7lx5n5gd9gb4jr2jo5ck9a&subtitles=burn&Accept-Language=zh (8 live) TLS GZIP 3773ms 1155 bytes (pipelined: 3)
May 06, 2018 19:13:20.875 [0xe83ffb70] INFO - CodecManager: obtaining decoder ‘h264’
May 06, 2018 19:13:20.875 [0xe83ffb70] DEBUG - HTTP requesting GET https://plex.tv/api/codecs/h264_decoder?build=linux-synology-i686&deviceId=a4bae751-0362-44e0-acf4-f8f47d6677b8&oldestPreviousVersion=1.12.3.4973-215c28d86&version=7814ac9-1285
May 06, 2018 19:13:21.863 [0xe83ffb70] DEBUG - HTTP 200 response from GET https://plex.tv/api/codecs/h264_decoder?build=linux-synology-i686&deviceId=a4bae751-0362-44e0-acf4-f8f47d6677b8&oldestPreviousVersion=1.12.3.4973-215c28d86&version=7814ac9-1285
May 06, 2018 19:13:21.863 [0xe83ffb70] DEBUG - HTTP requesting GET https://downloads.plex.tv/codecs/7814ac9-1285/linux-synology-i686/libh264_decoder.so
May 06, 2018 19:13:34.287 [0xf0111b70] DEBUG - handleStreamRead code 335544539: short read
May 06, 2018 19:13:34.481 [0xf03ffb70] DEBUG - Auth: authenticated user 1 as myhcloud
May 06, 2018 19:13:34.481 [0xeb3ffb70] DEBUG - Request: [192.168.1.237:55905 (Subnet)] GET /player/proxy/poll?deviceClass=pc&protocolVersion=1&protocolCapabilities=timeline%2Cplayback%2Cnavigation%2Cmirror%2Cplayqueues&timeout=1 (5 live) TLS GZIP Signed-in Token (myhcloud)
May 06, 2018 19:13:34.481 [0xeb3ffb70] DEBUG - Beginning read from two-way stream.
May 06, 2018 19:13:42.955 [0xe7bffb70] DEBUG - Request: [127.0.0.1:43469 (Loopback)] GET /library/changestamp (6 live) GZIP Signed-in Token (myhcloud)
May 06, 2018 19:13:42.955 [0xf03ffb70] DEBUG - Completed: [127.0.0.1:43469] 200 GET /library/changestamp (6 live) GZIP 0ms 463 bytes
May 06, 2018 19:13:54.483 [0xf03ffb70] DEBUG - handleStreamRead code 335544539: short read
May 06, 2018 19:13:54.665 [0xf03ffb70] DEBUG - Auth: authenticated user 1 as myhcloud
May 06, 2018 19:13:54.665 [0xeb3ffb70] DEBUG - Request: [192.168.1.237:55914 (Subnet)] GET /player/proxy/poll?deviceClass=pc&protocolVersion=1&protocolCapabilities=timeline%2Cplayback%2Cnavigation%2Cmirror%2Cplayqueues&timeout=1 (5 live) TLS GZIP Signed-in Token (myhcloud)
May 06, 2018 19:13:54.666 [0xeb3ffb70] DEBUG - Beginning read from two-way stream.
May 06, 2018 19:14:14.668 [0xf0111b70] DEBUG - handleStreamRead code 335544539: short read
May 06, 2018 19:14:14.856 [0xf03ffb70] DEBUG - Auth: authenticated user 1 as myhcloud
May 06, 2018 19:14:14.857 [0xe7bffb70] DEBUG - Request: [192.168.1.237:55923 (Subnet)] GET /player/proxy/poll?deviceClass=pc&protocolVersion=1&protocolCapabilities=timeline%2Cplayback%2Cnavigation%2Cmirror%2Cplayqueues&timeout=1 (5 live) TLS GZIP Signed-in Token (myhcloud)
May 06, 2018 19:14:14.857 [0xe7bffb70] DEBUG - Beginning read from two-way stream.
May 06, 2018 19:14:14.966 [0xe83ffb70] ERROR - Error issuing curl_easy_perform(handle): 28
May 06, 2018 19:14:14.966 [0xe83ffb70] DEBUG - HTTP simulating 408 after curl timeout
May 06, 2018 19:14:14.966 [0xe83ffb70] ERROR - Codecs: Download failed: Failed to download ‘https://downloads.plex.tv/codecs/7814ac9-1285/linux-synology-i686/libh264_decoder.so’: 408
May 06, 2018 19:14:14.966 [0xe83ffb70] ERROR - Error configuring transcoder: Decoder install failed: h264
May 06, 2018 19:14:14.966 [0xe83ffb70] DEBUG - Streaming Resource: Terminated session 0xe9e13194:nqni3pvso9q1shkfx5b9hmjg with reason Conversion failed. A required codec could not be found or failed to install.
May 06, 2018 19:14:14.966 [0xea3ffb70] DEBUG - Killing job.
May 06, 2018 19:14:14.966 [0xea3ffb70] DEBUG - Job was already killed, not killing again.
May 06, 2018 19:14:14.966 [0xea3ffb70] DEBUG - Stopping transcode session tv7lx5n5gd9gb4jr2jo5ck9a
May 06, 2018 19:14:14.967 [0xe8bffb70] DEBUG - Cleaning directory for session tv7lx5n5gd9gb4jr2jo5ck9a (/volume1/Plex/Library/Application Support/Plex Media Server/Cache/Transcode/Sessions/plex-transcode-tv7lx5n5gd9gb4jr2jo5ck9a-9b30a874-a750-41a0-8155-ec7939c7fde9)
May 06, 2018 19:14:14.967 [0xf03ffb70] DEBUG - Completed: [192.168.1.237:55899] 404 GET /video/:/transcode/universal/start.mpd?hasMDE=1&path=%2Flibrary%2Fmetadata%2F1&mediaIndex=0&partIndex=0&protocol=dash&fastSeek=1&directPlay=0&directStream=1&subtitleSize=100&audioBoost=100&location=lan&addDebugOverlay=0&autoAdjustQuality=0&directStreamAudio=1&mediaBufferSize=102400&session=tv7lx5n5gd9gb4jr2jo5ck9a&subtitles=burn&Accept-Language=zh (5 live) TLS GZIP 55815ms 452 bytes (pipelined: 1)
May 06, 2018 19:14:15.031 [0xea3ffb70] DEBUG - Transcoder: Cleaning old transcode directories.
May 06, 2018 19:14:15.031 [0xea3ffb70] DEBUG - Whacked session tv7lx5n5gd9gb4jr2jo5ck9a, 0 remaining.
May 06, 2018 19:14:16.038 [0xf0111b70] DEBUG - Auth: authenticated user 1 as myhcloud

1/2 a log is not very helpful, but looks like your server has network issues stopping it connecting to the internet.

full logs

i can link to my server outside my network

  1. Download the 64 bit PMS from Plex.tv/downloads but do not yet install it. The version you get from Synology is the 32 bit version. You’ll be much happier with it on your XPEnology environment.
  2. Stop PMS
  3. Open Control Panel - Shared Folders - Edit the Plex share - Permissions tab - Give your username R/W permission
  4. Open File Station -> Plex / Library / Application Support / Plex Media Server / Codecs
  5. Delete everything in the Codecs directory
  6. Install the 64 bit version of PMS and allow it to start
  7. Now play an H.264 movie or episode. Allow the few extra seconds for it to download the codec fresh.

Be advised, if you are running DSM 5.2 in XPEnology, support for 5.2 DSM will soon be frozen

I can’t install 64bit pms because it told me not surport dsm 5.2。

Then it’s time to upgrade your XPEnology.

Your logs definitively show the i7/4790. Synology doesn’t make any products with that processor

May 06, 2018 19:08:02.639 [0xf3111b70] INFO - Plex Media Server v1.12.3.4973-215c28d86 - synology DiskStation i686 - build: linux-synology-i686 synology - GMT 08:00
May 06, 2018 19:08:02.639 [0xf3111b70] INFO - Linux version: 3.10.35 (#1 SMP Tue Feb 2 17:44:24 CET 2016), language: en-US
May 06, 2018 19:08:02.639 [0xf3111b70] INFO - Processor Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz

I changed cpu myself。
this is not the key。

I found 408 err in the logs,I can’t download the decoder in real time,Can plex provide offline package of all decoder pms need?

There is nothing which can be downloaded offline. Codec licensing requires codecs be downloaded and associated with an active server. Once downloaded by the server and installed, the server can be taken offline.

If you created a non-standard Synology configuration, cannot upgrade Synology DSM 6 yourself (which you should be able to if Synology didn’t block that NAS model from being upgraded to DSM 6), and cannot load XPEnology 6.x, there is absolutely nothing which I can do to help you.

So that I better understand, which model did you change the CPU in?

it work,thanks a lot。