Do you mean you have it blocked in a URL-filtering profile that is assigned to the wetransfer rules or somewhere else? If the former is the case then you simply need to use a URL-filtering profile with either all categories set to "alert" or, better, set only malicious categories to "Block" (see "Block Recommended" section in this article https://live.paloaltonetworks.com/t5/blogs/url-filtering-category-recommendations/ba-p/325701) and all others, including the "Online Storage and Backup" category, to "Alert". If the latter is the case, well, then you need to allow it somehow... There are several ways of achieving this depending on your environment and business requirements. For example, you could have the same AD group assigned to the "wetransfer" rule and a rule that would allow "ssl and web-browsing" to the "Online Storage and Backup" category (that category would need to be set as the matching criterion, on the "Service/URL category" tab; the URL profile in that rule would need to be set to "Alert" only on all categories).
... View more