Outlook Issues when Sending email

I'm running MS Office 365 2013 Office, installed locally on our computers, Windows 7 - 8GB.
I have two clients who have sent out emails only to have them stick in the Outbox. Nothing I do sends the email out it remains stuck there. But when the Outlook product is closed and reopened the emails are gone, "I mean gone" not sent or sitting anywhere within the client, the end user must remember what they typed and retry sending them again. It usually gets sent out the second time around.

On top of this the product is also sluggish on some systems and not others.

I have tried removing plugins, and I tried few other things found online for both issues but without luck.

Any help would be greatly appreciated!
Joe RuddManager ITAsked:
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JohnBusiness Consultant (Owner)Commented:
Office 2013 generally works fine on Windows 7, Windows 8.1 and 10. Given your description, I would try two things:

1. Check for viruses and malware with your own Anti Virus application. Then scan with Malwarebytes in Safe Mode.

2. On one or both problem computers, set up a new, test, Windows User Profile (Account) and test Outlook in the new Windows Account.

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Joe RuddManager ITAuthor Commented:
Thanks JohnH,
We've already done both of those, I must admit that it hasn't happen since we've made the adjustments, but I worry that it isn't over.
JohnBusiness Consultant (Owner)Commented:
Thanks and if you have troubles, just ask again.
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