Sometimes, a user may not see the invitation in their inbox because it was deleted or went to the "Spam/Junk" folder. It may also have been blocked by the IT team in your company.
In such cases, you have the option to resend the invitation. To resend the invitation, go to "Account > Users & Permissions" under Settings.
Locate the user who needs to be re-invited, click the 3-dot menu of the user, and click "Re-invite."
Cloud will send the email again to the email address to which the first invitation was sent.