URL redirection not working after permalink change

Hi,

I recently changed the permalink structure on my blog from /%year%/%monthnum%/%postname%/ to /%postname%/. WordPress should automatically 301-redirect the old URLs to the new ones, but it’s not doing so for some reason. I tried the Simple 301 Redirects plugin, and even it doesn’t help.

I am not sure what the issue is, and would really appreciate if someone takes a look.

Blog is https://techorbiter.com

Old URL example: https://techorbiter.com/2015/06/sharex-for-windows-kicks-ass/

Thanks!