Comment by localtoast

I have found adding the following four lines to the immich proxy host in nginx proxy manager (advanced tab) solved my immich syncing issues:

client_max_body_size 50000M;

proxy_read_timeout 600s;

proxy_send_timeout 600s;

send_timeout 600s;

FWIW, my library is about 22000 items large. Hope this helps someone.