wordpress category page 404

Question

I have updated a category slug and now my category page for that category is displaying a 404. I have tested doing this on a staging site and it works fine but when I do this on production for some reason I get a 404. I have,

• resaved permalinks hundreds of times
• deactivated plugins
• disabled all caching
• restarted my server

I am completely confused and cannot understand why wordpress is so fragile around permalinks and urls.

Thanks

Answer 1

I went to Settings > Permalink, I changed nothing, validated and... it worked. Perhaps a default setting was missing.