Hotmail and other Microsoft companies started blocking our mail server IP rejecting all e-mails sent to them. We do not send spam nor have mailing lists but somehow the blocked us all the same.
I've contacted Microsoft Support but they simply won't help. Our ISP is not responding either so we are all alone facing this problem.
I thought I could setup the Zimbra server to use another unblocked SMTP server while we wait for the Microsoft Technical Support to add our IP/Domain to their Whitelist.
Is this possible?
Thank you in advance,