This very issue was discussed earlier tpday, and the asker found the solution acceptable.
Link to the previous discussion (https://www.experts-exchange.com/questions/28980200/Cablevision-email-problem-when-sending-from-inside-Cablevision-Optonline.html#a41868375%29)
This video shows how to remove a single email address from the Outlook 2010 Auto Suggestion memory.
NOTE: For Outlook 2016 and 2013 perform the exact same steps.
Open a new email: Click the New email button in Outlook.
Start typing the address: …
Many of my clients call in with monstrous Gmail overloading issues with Outlook. A quick tip is to turn off the All Mail and Important folders from synching. Here is a quick video I made to show you how to turn off these and other folders in Gmail s…