Constant failed attempts to Sync

Looking at my PMS logs, I see a lot of the following;

11:01:20.272 [0x7f4e79511700] WARN - Sync: sync list 8360740 belonging to user 1 has died of old age, ignoring
11:01:20.303 [0x7f4e79511700] INFO - Sync: downloaded 2 sync list(s) with 29 sync items(s): 0 new, 0 updated, 0 deleted
11:01:21.372 [0x7f4e79511700] WARN - Sync: sync list 8360740 belonging to user 1 has died of old age, ignoring
11:01:21.422 [0x7f4e79511700] INFO - Sync: downloaded 2 sync list(s) with 29 sync items(s): 0 new, 0 updated, 0 deleted
11:11:02.961 [0x7f4e853c5700] WARN - Sync: sync list 8360740 belonging to user 1 has died of old age, ignoring
11:11:02.992 [0x7f4e853c5700] INFO - Sync: downloaded 2 sync list(s) with 29 sync items(s): 0 new, 0 updated, 0 deleted
11:11:03.657 [0x7f4e79511700] WARN - Sync: sync list 8360740 belonging to user 1 has died of old age, ignoring
11:11:03.689 [0x7f4e79511700] INFO - Sync: downloaded 2 sync list(s) with 29 sync items(s): 0 new, 0 updated, 0 deleted
11:19:13.022 [0x7f4e78f35700] WARN - Sync: sync list 8360740 belonging to user 1 has died of old age, ignoring
11:19:13.053 [0x7f4e78f35700] INFO - Sync: downloaded 2 sync list(s) with 29 sync items(s): 0 new, 0 updated, 0 deleted
11:19:13.660 [0x7f4e78f35700] WARN - Sync: sync list 8360740 belonging to user 1 has died of old age, ignoring
11:19:13.691 [0x7f4e78f35700] INFO - Sync: downloaded 2 sync list(s) with 29 sync items(s): 0 new, 0 updated, 0 deleted

Anyone have any idea what is going on? How do I debug this?

I am having a similar issue this morning. I tried to sync Trolls to my daughter’s tablet and it just stays in a pending state. I couldn’t discern from the logs what the issue is other than it almost seems to be stuck in a loop trying to update sync items. I also had a similar line as javerre:

May 14, 2017 08:44:43.091 [7804] WARN - Sync: sync list 4629726 belonging to user 1 (xxxxxxxx) has died of old age, ignoring

However, I also tried to sync a single song to my phone (The 1975 - Somebody Else.flac) and the exact same thing happened. I did locate this line in the logs that sounds like it would be a definite problem.

May 14, 2017 07:37:19.201 [1872] DEBUG - MDE: analyzing media item 597918
May 14, 2017 07:37:19.201 [1872] DEBUG - Somebody Else - audio.bitrate limitation applies: 932 > 480
May 14, 2017 07:37:19.201 [1872] DEBUG - Codecs: testing mp3_mf (encoder)
May 14, 2017 07:37:19.202 [1872] WARN - Failed to find encoder 'mp3_mf'

Not finding the encoder sounds like a problem anyway, but what’s interesting to me is that I turned around again @ 9:13am and tried to sync using ‘Original Quality’ so the need for an mp3 encoder would be gone since the original format is FLAC and the same series of events still came up in the logs.

Logs are attached.