Supplier admin user is not getting an email with the url to set a password to access supplier portal

Summary:

Our external suppliers are self registering as spend authorized suppliers. After they register as admin users and also checking the checkbox to create user account, they are not getting the email containing a url to setup a password to allow them to login to supplier portal.

Anyone facing this issue recently and any suggestions.

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):