sent item stuck in outbox if an attachment is larger than 1gb

If I am sending emails containing an attachment of 1gb or larger the email remains in my outbox and does not get sent. Also I do not get any pop ups or error messages to let me know. Any idea if this is a setting issue? thanks all

Most providers do not allow such large attachments to be sent, and also most recipients will not be able to receive them. Look in Menu > Tools > Operations, and see if there is an error from your server in the Log tab.

As a general rule, 10MB is probably the maximum safe size, and by default eM Client is configured to notify you when your attachments exceed that.

Hi Gary
So so sorry, I meant attachments over 1mb mean the email sticks in my outbox (not 1gb as would normally wetransfer anything close to that size)

Go the Menu > Tools > Accounts and click on the SMTP tab for the account in question. Make sure that the port is set to  587 and the security policy is Force usage of SSL/TLS. See if there is any difference.