Cron command not working that works as user

I am trying to get a backup command to work that sends my database backup offsite to an AWS bucket.

The command works fine when executed from the console but it won’t work when it runs with cron.

This is what I am currently trying to do:

0 0 1 * * sudo -u david81 “/home/david81/backup_mongo.sh”

I have tried other versions of the command but I don’t remember what they were.

Any ideas why this command will work from the console but won’t work with cron?

Thanks.