Since few days the Spam Check detect one issue.
I found why after several tests.
If I active more than one Link Tracking the spam check detects this issue:
A URI hostname has long a (6 characters or more) hexadecimal sequence. This looks suspicious.
Indeed, if the Link Tracker is activated all links are modified in order to track user interactions.
That’s weird because I always used the link tracking for all links in my emails. (social, call to action, link to my website)
If I test my email with mail-tester.com, I got score of 7.3 points, before I got a score of 9.3 pts…