Hi Halid,
A lot has been written about the infamous OutOfMemory error, but not that I recall when sending email. See also the 'Related content' section at the bottom of this screen.
Also solutions such as GarbageCollection have been suggested before, and seem to have given results in some cases.
However, I assume most tips provided for on this forum would apply even to your case. While 6Mb may sound rather small to get this error, it is likely the combination of juggling Outlook and the attachment that is the showstopper here.
In our office, our processes never send attachments in email. Instead, we copy the link to the document into our email body. But obviously, this only works when your email is an internal email and where the recipient has access to its location.
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Happy coding!
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Paul
Sweden
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Happy coding!
Paul, Sweden
(By all means, do not mark this as the best answer!)