Wrong midnight for feeds

Hello guys,
I’m a newbie in this forum,
I need some help with a problem about Arduino EmonTx shield.
When I try to graph kWh/d on emoncms.org, it starts from 1 am instead of from midnight.
The path I follow is Setup → My Account → Timezone.
Even though I tried to change my time zone from Europe/Rome to others, I didn’t saw any difference: my graph always starts at 1 am.
How to change it?
Thank you!