Outlook not storing sent emails I use Gmail

Hi. I'm at a loss with Outlook. None of my sent emails are being stored in Outlook even though the IMAP settings are all correct. There's times I have to stop using Outlook all together because it won't even open on my desktop. I do not like using the online Outlook. Who can I call to help me figure this out? Outlook was good to me for so many years and now its just a headache.