Hi Mouda,
I tested 2 customer journeys as yours:
1 for send test email, then all my test recipients unsubsribed by checking Do not email link.
2 is to send them another test email again, then I found email has been blocked for all of them due to the option was set.
Please do following check:
1. Open your subscription center form, check whether your contacts have submitted with their preference successfully in Insights > Form Submission:
2. Check whether the option has been really set to Do not allow in contact form:
I didn't encounter your issue in my environment: Version 1710 (9.1.0.10334)
The expected behavior should be that once contact checked the option, then he/she won't receive any marketing email again regardless of he/she is a member of any marketing list.
If above steps are all no problem, please open a support ticket for investigation on instance:
https://admin.dynamics.com/?referer=mbssupport
Regards,
Clofly
