If you use Outlook 365 to forward emails to HelpSpace you might get an error like the one below:
550 5.7.520 Access denied, Your organization does not allow external forwarding. Please contact your administrator for further assistance. AS(7555)
This error means that you are not allowed to forward emails to an external Domain. The solution is to enable automatic email forwarding to external addresses inside your outlook 365 account.
Please refer to the official documentation in order to enable external forwarding: