Support Forum

sorry, but not sure what you have tried from your post... on forum - components - seo, there are five options alone for the meta description... and some require you to fill in the description...

additionally, your seo plugin may be overriding what we try to set...  does it have options/settings on the actual wp page?  you probably have to disable it from the wp page the forum is on...

so you are not seeing a meta description in the head tag?  or two?

not suggesting you change, but the two seo plugins that we know play very well with simple press are Yoast WordPress SEO and All in One SEO...  another case where seo plugins get confused by dynamic content on a single wp page... they try to write their stuff on all the forum pages ignoring rewrites and canonical urls...