Our site reports 403 forbidden error when we are not logged in our site. However, our site will be ok when we have logined, which is confusing. We checked our wordpress, then we find the problem.
Why does wordpress report 403 forbidden error if you are not logged in?
This error may be caused by some wordpress cache plugins.
When you have logined, these plugins may do not cache files. However, if you sign out, these plugins will save cached files. If there are some wrong with these cache files, wordpress may report 403 forbidden.
How to fix 403 forbidden error?
As to us, we have installed W3 Total Cache plugin, however, this plugin cause wordpress 403 forbidden error.
To fix this error, we deactivate it, then we find this 403 forbidden error is fixed.
In order to speed up our site, we install wordpress cache plugin LiteSpeed Cache instead.