WordPress Plugin / CMS Does Not Allow New Domain Emails

Simple problem - but not easily solved! I installed the All-In-One Kaltura Wordpress plugin. Worked great - then I went to login to the CMS to look at more advanced features. After installing the plugin, getting the email, changing my password and uploading a test video - I decided to login to the CMS, only to be denied entry because the CMS that was attached to my WP account didn’t recognize new domain names: name@company.digital was not allowed by the login. So, I figured I would use a different email address, deleted the plugin and began the process all over again BUT when I reinstalled the plugin - it recognized by email and account number - so no CMS login. Any help appreciated!