1. Go to the Wordpress admin login page :
2. Enter the credentials and log in
3. Create a test post and save it
4. Now edit it in classic editor and change the permalink to anything.
5. The yoast redirect will pop up on above telling you that redirect has been added. Remove that by clicking on undo.
6. Open yoast redirect manager, if any redirection for such URL is there then remove it otherwise create a redirection entry.
for example: if permalink is anything then redirection would be: from something to anything.