URL Redirection being blocked?

[r1der]

Good morning,

We have a spam filter, which rewrites any URL in an email.

Today, we encountered an issue with that, possible due the the string being too long is my guess. Under an account that is allowed any external, I was able to reach the redirect and the sites they go to.

An example of my issue is below, except with this example, the redirection is working. I am thinking because it isn't as long as the one I am having an issue with. The URL I am having with is double this lenght, which I am thinking might be the issue.

E.g. this is how the URL would look like.

https://urldefense.com/v3/__https:/www.checkpoint.com/eLearning__;!!FKv5UbzFF59DNjfn2A!XqhrfMzFM9UVp...

This is where it goes.

https://www.checkpoint.com/eLearning/. 

I've identified what rule is stopping it under my Security layer, however I'm not sure what kind of exception to make for this. 
As 

The destination is not showing as Drop or Reject (urldefense.com/sched.com). So not sure what exactly I should be allowing through if I can reach the destinations directly. just not when it has the URL rewritten by the spam filter.

I tried searching but possibly not using the right terms. Can anyone help lead me in the right direction?

Thank you,