Good news Galaxy Tab S2 9.7 Wi-Fi people! Whatever was causing the builds to fail has apparently been fixed. I gave it another try today, and was able to build the latest e-0.14 for gts210vewifi with no problems. I have the image running on my tablet right now, it all looks good.
For whatever reason, the project’s official test build for this device has not been updated since e-0.10 in August 2020.