Anyway, I tried the following:
- koha-rebuild-zebra -b -f -v <database name>. It seemed to rebuild successfully albeit with a few errors regarding a few specific records (but I think that's unrelated)
- I followed some of the steps outlined in the wiki entry about Troubleshooting Zebra (https://wiki.koha-community.org/wiki/Troubleshooting_Zebra), namely:
  - under Searching and Searching Issues, I tried connecting with yaz-client -c /etc/koha/zebradb/ccl.properties unix:/var/run/koha/$instance/bibliosocket. It gives out the following error: Connecting...error = System (lower-layer) error . I tried searching for more information on this error but without success
  - Under the same wiki entry, regarding indexing issues, it says to do a manual re-index but the link goes nowhere. I'm guessing the FAQ entry mentioned is on the Koha manual under "Reset the Zebra Index"? But what does this mean, exactly? Am I going to lose both biblios and authorities records? I don't think so, but still