Roundcube webmail not working

[ChandraHeald]

Hi our work emails are on roundcube webmail . When I'm connected to the WiFi on my personal phone (iPhone) and the work phone (android) it won't let me login but if I turn the WiFi off it works and allows me to login it's also done this on my personal phone over the weekend when trying to purchase something . As soon as I turn my WiFi off it works 

[Mark39]

Are you able to log in here over wifi: https://www.sky.com/signin/email ?