hdd error

Having a + symbol in an email address is a RFC standard (Email address - Wikipedia) but I can't get the Hikvision setup area to accept it when I try and input an email with a "+" in the Configuration > Network > Advanced Settings > Email area: Is this just a bug/limitation of the firmware...

A friend has a DS-7608NI-SE8P. The hdd management screen shows zero space available. He is getting exceptions and turns the unit off when he is on-site, because it constantly beeps. When I access the unit remotely -I don't see any options to allow old data to be written over. When I go...