Custom webhook broken in 2.2 (worked in 1.3)?

We upgraded some environments to 2.2 but it seems it boke our custom webhook. It’s a very simple one, just a server:port with an extension, nothing complex. We have some environments still at 1.3 and the exact same setup works. If I try a test message I get an error

“[status_exception] statusText is null or empty”

I will say I have a VM running the the opensearch-2.2.0/opensearch-tar-install.sh and running a simple Python webserver with Flask and it works so not something broken with the version. It’s just a strange error and the message is not much help.
TIA