Do I need to delete daily cache

Hi,

I have a migrated users from my site which was previously on bigcommerce to wordpress recently. The problem I am having is that I was not able to transfer the passwords for any of the users, I was only able to transfer their username which is their email.

My users have been told to create a new password and then use that password to login. Every one of them when they try to do this are not able to login with their new password immediately. I found out that unless I delete the cache of the site WordPress will not recognize the newly created password.

It seems like I will have to delete the cache daily until all of the users have recreated their passwords. Am I correct? If so how would I go about setting this up in this plugin?

https://wordpress.org/plugins/wp-fastest-cache/