Outgoing Mail Server Connection Failed

I keep getting this error when I try sending Mail Drop Attachments from my Yahoo mail account, to a Hotmail account on my home desktop. I'll get a message saying, "The connection to the outgoing server apple.smtp.yahoo.com failed. Additional Outgoing Mail Servers can be configured for Mail accounts in Settings>Mail>Accounts". When trying to send files with WeTransfer as an alternative, the emails aren't sent out. This issue only appeared with this update. Deleting and re-adding my my account does not resolve the issue.