Can't send emails in Mail app after macOS Tahoe update on MacBook Pro

Following Taho update my apple mail has become almost unusable. For last several days I can't send email.I 'm IMAP using Network Solution hosting. Have seen other reports that users of Apple Mail can't send email after Taho. For me it's a disaster. Have to use google mail instead

[Re-Titled by Moderator]

Original Title: apple mail smtp issue after taho update