How to post a block of code without my post being rejected for "images, videos,..."

This is my first post. Needed hep deciphering an excel formula. I pasted the formula in a code block. Submitted form. Validation said I was trying to post a link or video or whatever and I can't cos I'm a newbie and need to post a few times first.
Anyway, at least this post will count as one of the few I need to post before I can post some code which isn't an image or video or link

Hi and welcome
what do you mean by " code block" ?
You can enter a formula without difficulty no tags or anything needed, just be aware that < or > must be preceded by a space, otherwise the board thinks it's a virus