We have a SharePoint application hosted on an azure VM. There are a number of notifications sent out from the application at various stages. We are using Send Grid for sending emails. Everything was working fine for around a year. A few days back, we noticed that no notifications were being sent. When I tried to find out the cause of the issue, I found that no activity was logged in the Send Grid server. I tried telnet smtp.sendgrid.net 25, and that too failed with the message “Could not open connection to the host on port 25”. It seems all communications with the Send Grid server are getting blocked.
Can someone help?