Dashboard not working after activating Multisite

Fairly new to this so please excuse my ignorance.

I have a website hosted by Bluehost on which I had set up a subdomain previously (don’t recall why I did that, but I did). The subdomain functions as a standalone site also.

https://www.mysite.com
subdomain1.mysite.com

I want to set up a testing area for redesigning my site so I thought Multisite made sense. I backed up my wp-config file. Using Notepad++, I added the following before /* That’s all, etc */:

/* MULTISITE */
define ( ‘WP_ALLOW_MULTISITE’, true)

I uploaded the revised wp-config, refreshed my Dashboard and get a blank page. I deactivated all plugins and tried again. I upload the original wp-config back to the site and everything works until I try to activate Multisite again.

I cannot figure out what I am doing wrong. Any help would be appreciated.