OE won’t allow attachments

Emails from my other computer (in an effort to get messages over to new computer) have a header “OE has removed access to the following unsafe attachment”.
How was that gate installed, what/who controls it? How can I change it?
I KNOW that this are safe attachments but it not let me open them. I am a recruiter, these are resumes I need! HELP!!!!
Again, thanks in advance for your simply worded assistance as I am as my tag suggests: not a techie.