Hi Sun_Ad,
I'd like to confirm the following things:
1. Does this issue occur in Office 365 OWA or Outlook desktop client?
2. If your e-learning system sends emails to Hotmail or Gmail, will this issue occur?
In general, if the URL in the email cannot be recognized as a standard safe URL, this URL will be blocked in Outlook Web App. This kind of behavior is not a configurable feature in Office 365. For all the URLs that can be recognized, it will be fine to open in Outlook Web App.
Thanks,
Edward Qu