Hi @Rups ,
Welcome to our forum!
In order to verify the issue, please provide some related information:
What type of account are you using? Is it an Exchange Online account?
Do some users have this problem or do all users have this problem?
Have you ever tried sending another safe link?
Check if the user configured any junk email settings. you could let the user manually configure safe sender or admin can use powershell to meet this need as well.
Detailed information can be seen here:
Block or allow (junk email settings)
Configure junk email settings on Exchange Online mailboxes
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.