Hello everyone

Hopefully, someone could help me with this Problem. I just made a new company account with five different mail addresses. So far, I only have 1 contact in my address book, with 3 different mail addresses. Though he's registered in my contacts, his mails always land in the spam folder. That's quite annoying, because when I synchronize the mails on my cell, I don't receive these mails. Any ideas, where the problem lies?