Like other email service providers AOL also uses SMTP protocol for sending users to mail Now SMTP server may be disturbed due to incorrect settings for email clients. Clearly, it will create issues for sending and receiving emails. You need to fix the issue to resume the AOL service. Contact at AOL helpline numberand get fixed. Expert advice with the professional approach of the solution. An easy approach to review the settings and alter the incorrect changes will surely be fixing your issues.