Our colleague tried to reset his password but no e-mail reached him. I checked exchange e-mail record but there have been no e-mail rejected/failed related to his e-mail address. We would like you to check your e-mail record as sender and please advise how we should inform his e-mail address.
Your kind cooperation will be appreciated.
Hello
As a first step, please have him check this article: Troubleshooting Issues with Email Notifications. It provides some helpful steps to resolve the issue, such as checking the spam/junk folder, verifying the firewall or email security policy, ensuring the email isn’t on the suppression list, and more.
If he’s still unable to receive the email to reset the password, please advise him to submit a ticket to our Product Support team for further assistance.
Looking forward to having this sorted out. 
Hello, Thank you for your detailed response. I checked troubleshooting and tried accordingly but he can’t receive reset e-mail yet. Also, he can’t log in BOX support as his password is unclear.
Is there any good solution that he can reset his password without receiving e-mail? Or, is it possible to fully delete his account so that he can remake his account? As of now, there is no data in his box.
Your kind cooperation will be appreciated.
Dear
The only way to reset the password is via the password reset email. However, we can check if your colleague’s email address is on our bounce list, which may explain why they’re not receiving the reset link. This sometimes happens when multiple confirmation emails are requested in a short time.
If your colleague is using a free personal account, we do not recommend canceling it. According to our deletion policy, deactivated free accounts will be removed from our system only after a certain period of time. Upon cancellation, the same email address cannot be used to sign up again immediately. We apologize for any limitations this may cause.
In the meantime, we’ll escalate this to our Product Support team. You’ll receive an email with a case number shortly. Please respond to that email with the affected user’s email address and copy them on the thread for account verification purposes.
We hope this helps and look forward to getting this resolved as soon as possible. 
Hello. Well noted. I received e-mail from your product support team and will make contact with them.
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.