I have my nextcloud running on Debian 8, I also am using the sync client to keep a copy of the files on my computer. I have my video surveillance set to copy the files to my (Windows based) FTP server. This folder happens to reside in the nextcloud share tree. This has been working well since I originally installed it.
Recently I started getting some failures in syncing the files up to the server, but I don’t know where to start looking for the issue.
The error log shows this:
# timestamp | duration | file | instruction | dir | modtime | etag | size | fileId | status | errorString | http result code | other size | other modtime | other etag | other fileId | other instruction
#=#=#=# Syncrun started 2017-06-21T18:22:03
#=#=#=#=# Propagation starts 2017-06-21T18:22:08 (last step: 4995 msec, total: 4995 msec)
||Surveillance/Cam-FrontPorch/01_20170616045658.mp4|INST_SYNC|Up|1497614257|dd1a9c7862a43963b199e1064f711902|38061698|00186315ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170616045658.mp4-chunking-2673417508-4-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|6616999|1497614221|dd1a9c7862a43963b199e1064f711902|00186315ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170616010356.mp4|INST_SYNC|Up|1497600285|3ed75f27ce6780b6bef1513dab5fd9ea|44358634|00186279ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170616010356.mp4-chunking-2184256291-5-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|9722453|1497600243|3ed75f27ce6780b6bef1513dab5fd9ea|00186279ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170616050755.mp4|INST_SYNC|Up|1497614919|8fe21b07ca076e3cd0f8e579ec7c87cb|46545891|00186317ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170616050755.mp4-chunking-1647855520-5-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|5209956|1497614878|8fe21b07ca076e3cd0f8e579ec7c87cb|00186317ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170616053514.mp4|INST_SYNC|Up|1497616553|35c2153fddea8821365ed2129c1dca4f|35147483|00186319ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170616053514.mp4-chunking-385902406-4-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|3730006|1497616519|35c2153fddea8821365ed2129c1dca4f|00186319ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170616125436.mp4|INST_SYNC|Up|1497642924|ea9a65ef94b180403d7d79a303fb0aa6|47800187|00186364ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170616125436.mp4-chunking-111668306-5-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|5502747|1497642878|ea9a65ef94b180403d7d79a303fb0aa6|00186364ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170617104755.mp4|INST_SYNC|Up|1497721713|37dbd918f0b89f74548df7d04194b571|34976036|00186502ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170617104755.mp4-chunking-3908698046-4-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|7461940|1497721679|37dbd918f0b89f74548df7d04194b571|00186502ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170618010356.mp4|INST_SYNC|Up|1497773086|3530917d5008bc07840645dca329cf57|46054030|00186799ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170618010356.mp4-chunking-3813719053-5-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|5053028|1497773043|3530917d5008bc07840645dca329cf57|00186799ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170619010356.mp4|INST_SYNC|Up|1497859485|5111e662d2b441c6785f68fe209a4d12|45586831|00187598ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170619010356.mp4-chunking-3226483596-5-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|4275743|1497859442|5111e662d2b441c6785f68fe209a4d12|00187598ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170618173824.mp4|INST_SYNC|Up|1497832795|c4857cd2e43d1aaecb9b5c257cc2ae8c|88512127|00187371ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170618173824.mp4-chunking-3483404990-9-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|7427483|1497832709|c4857cd2e43d1aaecb9b5c257cc2ae8c|00187371ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170620144517.mp4|INST_SYNC|Up|1497995151|85cf9e602a510584af9472bee943e68b|31456595|00189265ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170620144517.mp4-chunking-2759989730-4-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|9413522|1497995121|85cf9e602a510584af9472bee943e68b|00189265ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170620152333.mp4|INST_SYNC|Up|1497997449|1c3c08960b73383e16b3fc552db50de4|33710379|00189431ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170620152333.mp4-chunking-955920117-4-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|9684057|1497997417|1c3c08960b73383e16b3fc552db50de4|00189431ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170620161007.mp4|INST_SYNC|Up|1498000241|7567fe5cebce563750cb054d7d27fe9e|31550367|00189536ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170620161007.mp4-chunking-843989823-4-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|9606344|1498000211|7567fe5cebce563750cb054d7d27fe9e|00189536ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170621010355.mp4|INST_SYNC|Up|1498032286|cae75fcafb6bb60a19edabc7c67bc989|47319670|00190974ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170621010355.mp4-chunking-1403294610-5-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|6763369|1498032243|cae75fcafb6bb60a19edabc7c67bc989|00190974ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-FrontPorch/01_20170621160249.mp4|INST_SYNC|Up|1498086205|1dc6a94177297665a1c531559e20569d|32444792|00192582ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-FrontPorch/01_20170621160249.mp4-chunking-1219127194-4-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|8882387|1498086174|1dc6a94177297665a1c531559e20569d|00192582ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-NorthWest/01_20170616223915.mp4|INST_SYNC|Up|1497677987|1ba8bf266d663016abf8881348b5fe6c|31348885|00186435ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-NorthWest/01_20170616223915.mp4-chunking-21564325-4-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|9354225|1497677956|1ba8bf266d663016abf8881348b5fe6c|00186435ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-NorthWest/01_20170617053434.mp4|INST_SYNC|Up|1497702911|369a088e3a2d0b68eb285a00bbe0114b|37310922|00186500ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-NorthWest/01_20170617053434.mp4-chunking-135777207-4-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|8561168|1497702878|369a088e3a2d0b68eb285a00bbe0114b|00186500ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-NorthWest/01_20170617121242.mp4|INST_SYNC|Up|1497726842|cc393c2aa7d4a7b5a7b8faeda7585f52|81648777|00186523ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-NorthWest/01_20170617121242.mp4-chunking-2236939756-9-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|8480679|1497726764|cc393c2aa7d4a7b5a7b8faeda7585f52|00186523ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-NorthWest/01_20170620181941.mp4|INST_SYNC|Up|1498008023|d26f72ded92dd80c2cc3b24111ac1c4c|38524348|00190286ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-NorthWest/01_20170620181941.mp4-chunking-2355966984-4-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|8456459|1498007985|d26f72ded92dd80c2cc3b24111ac1c4c|00190286ocxa1fszo3b2|INST_NONE|
||Surveillance/Cam-NorthWest/01_20170619200027.mp4|INST_SYNC|Up|1497927691|a718930c0b19243553cde909888ef2bf|61787852|00188821ocxa1fszo3b2|2|Error transferring https://my.nextcloud.domain/remote.php/dav/files/user.name/Surveillance/Cam-NorthWest/01_20170619200027.mp4-chunking-2535218704-7-0 - server replied: Precondition failed (An If-Match header was specified and the resource did not exist)|412|9041035|1497927631|a718930c0b19243553cde909888ef2bf|00188821ocxa1fszo3b2|INST_NONE|