Customers not receiving emails

Since about one month ago, our customers with @hotmail.com and @gmail.com email accounts are not receiving our emails from @ourdomain.com. They dont receive them at all or our messages are being classified as spam and sent directly to "junk mail".

I wonder if someone could help me and give me a hint about how to solve this problem, since our customers are not receiving their confirmation emails nor any other message sent by us.

Thanks for your time,
MikeX

Try TESTING several emails by switching your Email Transport method from sendmail to "sendmail -f" (which forces a bonafide sender name when messages are sent), or to SMTP/SMTPAUTH (and fill out the SMTP settings), which forces all your messages to be sent as if you were logged in to send emails from your own PC.

Admin->Configuration->Email Options

If it's getting classified as junkmail or spam, it's likely because the server is sending it by a default "[email protected]" address, which is a default setting of most servers.