Your company can use trusted certificates to secure communication with a mail server or a proxy server. When this is the case, you must import the certificates in the settings editor to make sure the controller recognizes them.
Ask your IT administrator, if there are:
Intermediate and root certificates used to access the mail sever, e.g. in case of a secure connection via SSL/TLS.
Intermediate and root certificates used to access any proxy for Internet access.
In case any of these certificates are used make sure you get them from your IT administrator.