This is a recent issue with wp4.0, and there is a bug fix outstanding for this.
The Issue
This gives 404 errors with sub forums for users with default permalinks. This is due to a bug in wp4.0, and netweb is on the case to get this fixed in 4.0.1
Three wordarounds
1. Change your permalinks to any of the other settings
Dashboard>settings>permalinks
The most often used is ‘postname’
This will not only fix your issue, but make your links look prettier. However if you have links to your site forums from other sites/emails, these links might break (ie they will come up as 404 errors), but if your choice is between users not accessing, or users complaining that the link in that old email no longer works, then resetting might seem a good idea.
2. revert to 3.9.2
see https://www.youtube.com/watch?v=_lX3E-qIpJM
for quite a good video on how to do it
3. Move your sub-forums up a level ie make them all main forums
and keep monitoring this site for a solution.
Thanks men 😉
I have a problem with “postname” permalink, when i checked all he links goes to error 404. I think is it because the WP don’t have access to the file .htaccess, I put the permisions at 775 to try, but have the same problem.. Can you give me some advice?
Now working permalink, and working forums!
Thanks¡¡¡