Hi my name is ***** ***** I will be the expert working with you today to help and resolve the problem you have posted.
Try to check the doc file size you are trying to attach as it must not exceed 10mb or else google blocks the file to be send further.
Try to zip up the file and make it less then 10 mb of size and then try to attach and send.
Let me know how it goes.
Try to set the browser to factory reset on IE and firefox using google which will give you steps how to reset your browser after that close the browser and reopen and then you are all set to send receive emails with attachment without any problem.
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