I had the same problem:
I set up Anthias with a LAN connection on the raspberry pi and an internet connection. The next day I tried the same raspberry pi connected to a router without internet (we use it at a fair in offline mode) and it did not work except for the two pictures uploaded with network connection. The others uploaded in offline mode did not appear.
TLDR:
Try setting the start date and time way back. My setup was offline and I think there was a problem synchronising the correct date and time.
This worked for me.