Credentials somewhere I can't find

Hello,

Our PRTG Server (just the one) is hammering our domain controller with requests every 2 minutes for the "Administrator" user credentials, and I can't for the life of me find where it even has them anymore since we tried to migrate to a service account and mail account just for it and for all of the probes and sensors (prtgadmin and PRTGServ respectively). I went through to make sure each of the servers and group was set to inherit from all the way up to root. I haven't gone through each sensor as we are nearing 800 at this time, but I would like to know if there are any gotcha's or commonly "hidden" places it could be, or common sensors that request alternate credentials.

Thank you