The Salesforce feature called "Organization-Wide Addresses" are meant to be generic email addresses that your outgoing emails can be sent from, to protect a user's email from being visible to the recipient.
When you edit each of these email addresses you are able to 'Allow Only Selected Profiles to Use the From Address' and then highlight the certain profiles.
Because improveit 360 uses a Custom Email Templates and PDF Generator, the system must query the Organization-Wide Address that are active when displaying in the 'From:' drop down for users.
The article linked below from Salesforce development team shows that improveit 360 is unable to query the Profiles that are selected and display only the Profile-specific Email Addresses to the logged-in user. This is because User Profiles are not a record type that is able to be inspected or queried.
The profile selection of the Organization-Wide Address is not compatible with improveit 360's Emailing Engine because Profiles are not able to queried and displayed.
If you choose "Allow Only Selected Profiles to Use the From Address" none of your Users (not even the System Administrator) will see this Email Address in the "From:" drop down menu when sending an email. See screen shots below: