When using ASP Classic and Office 365 email port 25 is the only port that works for sending emails.
When using ASP Classic and Office 365 email port 25 is the only port that works for sending emails. By default Azure VMs blocks port 25 traffic. It is suggested that you either use port 587 or open a ticket to have the port 25 open. There is also other option witch is enabling the IIS SMTP server and configuring it having Office 365 as the Smart Host at port 587 ... but it is not suggested. So my suggestions is to include this information to avoid "port 25 tickets".

Thanks for the valid suggestion. Your feedback is now open for the user community to upvote which allows us to effectively prioritize your request against our existing feature backlog and also gives us insight into the potential impact of implementing the suggested feature.