Enabling Email Subscriptions on Reporting

Need some assistance my fellow SSRS friends.

My company has an existing report server. All is working just fine when accessing and running the reports. However, when the server was set up, it was never configured for email subscriptions. I look in the Email option of the Report Server Config Manager and whoever made this server did fill out the required fields. However, subscriptions do not function.

I did a lot of searching last night and pretty much the results I found was to install the SMTP feature. I did this, but still nothing.

So I looked at an existing report server which is pretty identical as the problem server. However, the good server doesnt have SMTP set up and email subscriptions works just fine. I compared the good server settings to the bad server settings and they're pretty much the same.

Then this morning I logged into both server this morning to give see what's different. What I saw is that the good server has Active Directory set up and the bad server doesnt.

I guess my question is, does the report server require to have Active Directory installed? If not, what else can I look for to get this going? Thanks.

Let me know if more information is needed to assist.

Review the application config file for SSRS and verify whether or not the domain has been defined in the bad server. Also verify with the team that manages the SMTP server to see if they have a white list - and that the bad server has been added to the white list.