This is same question as this one reCaptcha doesn't support proxy configuration but for OJS 3. Is there any solution?
This has already been resolved in github for release in OJS 3.1 – see Recaptcha verification does not honor proxy settings · Issue #2367 · pkp/pkp-lib · GitHub for details. You should be able to pull the modification into your OJS 3.0.2 installation without much work.
Public Knowledge Project Team
Thanx for help, it is working now.