Duplicate emails sent when using email apps other than Yahoo Mail
Whenever I send an email from my sbcglobal account using any email app (including Outlook) other than Yahoo mail from my Samsung Galaxy S8+ Android smartphone, two copies of the message are sent to the recipient, and of the two copies in my Sent folder, one is marked as read, and the other is marked as unread. Duplicates are not sent when I use Outlook 365 on my laptop. I don't want to have to use the Yahoo Mail app to avoid this problem, and I can't find any settings that can solve the problem otherwise. Does anyone have a solution?