Major issue: broken URL's in a send e-mail

UPDATE: We think it is fixed now and that it was fixed automatically after several hours (the night went by) or that one of things we tried to fix it helped. We really have no clue about what happend

Your software
My Mautic version is: v2.16.3
My PHP version is: 7.2

Your problem
Today, we send a segment e-mail to a lot of contacts. When we tested it, all the URL’s worked perfectly fine. Two URL’s are going towards an asset which has been uploaded to Mautic and one to an external page.

However, in the mail that the users received, they will land on an 500 php error page instead of the external page or downloading the asset when they go to the URL.

We have tried all kinds of solutions, we tried to open it on multiple devices and browsers and we cleared the cache and cookies of the browsers.

Besides that, we have rebooted the server, cleared the cache and warmed it up.

We assume that is has to do something with the tracking code. At this moment, it is working sporadically.

Here is a working URL that was send in one specific e-mail:

Here is one that isn’t working:

Has anybody any clue about what happened and if and how we can fix it?