Hi @El Lababidi, Nur El-Hajat ,
Welcome to our forum!
Agree with Andy, it's suggested that you could log in to web mail and check if the issue still exists.
On the other hand, it's suggested that you could check your sent item folder to check if there's meeting canceling update. And you can also create a new meeting and check if the issue still exists.
In terms of Outlook client, it's suggested that you could try to use the Microsoft Support and Recovery Assistant to check if there're any problems, which works by running tests to figure out what's wrong and offers the best solution for the identified problem.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.