Hi Maxim,

Thanks for your help. I will investigate this and let you know. If the issue is on the mobile operator network, I will be pretty much stuck :-(

Or maybe I will have to decrease the MTU on my server.

I just checked: all the packets from the trace are sent with the "Don't fragment" bit set, and an IP size of 1500 (1516 ethernet).

What surprises me though, is that the issue arises sporadically. A mobile phone will have 1 request out of 4 failing (without changing of IP address)....