Microsoft has fixed an Outlook bug that blocks users from forwarding or replying to emails with embedded hyperlinks pointing to long URLs. The bug is known issue in Outlook for PC build 13913.10000, which should roll out in late April. Microsoft also provides a workaround for users affected by this bug until the fix will roll out. Microsoft is also currently investigating issues where the follow-up flag status is displayed in sent messages incorrectly and error messages being displayed when sharing a calendar in Microsoft 365.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-fixes-outlook-cannot-send-this-item-email-bug/