Problem to send email to hotmail

I always use EM CLIENT with workplace email ,
This week, when trying to send emails to hotmail, through EM CLIENT it gives an error and does not send, however, if I use my email server, works correctly.
Does anyone know what may be causing the problem?
Thank yu so much !

Can you give the error?

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its

recipients. This is a permanent error. The following address(es) failed:]

host hotmail-com-olc-protection-outlook_com []

SMTP error from remote mail server after pipelined MAIL FROM:<[------------@-------------t]> SIZE=4653:

550 5.7.1 Unfortunately, messages from [----------------] weren’t sent. Please contact your Internet service provider since part of their network is on our block list (S3150). You can also refer your provider to []

I already tried to unblock our ip in the hotmail blacklist, but at the end of the process he indicated that he was not there.

So you need to contact your Internet provider as the error says, because Microsoft is banning you from connecting through that provider.

Thank you soo much,
But email works correctly on other email servers (webmail, gmail) only in EMcliente this error happen