How to insert post into a page?

The likely issue here is you need to refresh your permalinks for it to recognise the post type. Classic fix is to go to Settings > Permalinks and then click Save Changes without actually saving anything. Just loading the permalinks setting page usually fixes it, but saving makes sure.

I’d say that’ll fix the issue.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)