I followed simple steps to use box application to share some business information with external stakeholder.
1. Created a folder
2. Uploaded my files
3. Clicked on share button at the top right corner and added the email addresses of folks I want to share with
4. Gave them viewer access

Result:
1. I can see in sharing panel these new users have pending requests
2. The users get email notification to access the folder but when they click they get an error 403.

It has happened multiple times, for some users the process is smooth, others it always throws errors. I have tried removing and adding them again but doesn't work.