I’m using WP 4.2.2 on NginX, with a multisite (subdomain) installation, and I have a strange problem. My site has about 18 posts and all post permalinks worked quite fine until this morning, when two of these links suddenly stopped working and showed a 404 error page.

These things I have already tried:

• Check if title and URL are WP reserved keywords (they aren’t)
• Empty browser and server cache, and try again (failed)
• Changed permalink settings to default (worked but I don’t want that)
• Edited permalink settings to default, date, category and back to posts name (failed)
• Deactivated all plugins (error is still active)
• Renamed post and changed URL (worked)
• Renamed post and URL, saved changes, undo changes and save again (fail)

I want to know what I have to change so that the broken links work again. I don’t want to check every morning to see which links are broken and have to be renamed.

NOTE: I updated translations this morning. I’m not sure if the problem already existed before that, but I think so.

I edited two of my posts and added pictures, moved them in the article and edited them. Suddenly those two posts don’t work either.