What OJS version are you using? This was merged in spring and is included in 3.1, but not in earlier versions. Merge pull request #2402 from ajnyga/use-context-specific-reply-to · pkp/pkp-lib@9b1b15a · GitHub also see Always use context specific reply-to address in notifications, if available by ajnyga · Pull Request #2402 · pkp/pkp-lib · GitHub and OJS3: notifications, sender and reply-to address