SyncThing, Lolipop, and "Transport endpoint not connected" I'm trying to get 2 way sync going with Syncthing on OctOS L (Lolipop, based on Cyanogen) with folders on the SD card.  Backup from Android to other Syncthings works fine.  The Syncthing devs say it's complicated to make things work properly on the SD card because of Google, and someone made a blurb on it.  Not sure why, but the fix doesn't seem to work for me.

I seem to be running into this issue, and the error I'm getting is weird, but more importantly, I'm not sure what Syncthing is doing to my SD Card.

Once Syncthing tries to write to the SD card, it fails, and then the SD card is unavailable to the rest of the system.  For example, Total Commander.  The only way I can get it back is to reboot the phone.  Using the built in Android tools, I cannot mount the SD card.

What does Syncthing do to the SD card when this happens?  Is it messing with the mount point?
Try different Sd card or your sd card might have a low space try Different method like Syncthing to otg or internal storage.