Email Inboxes: ssl3_get_record:wrong version number

When I send myself a test email, I see this in the logs:

{"level":50,"time":"2023-11-15T19:14:41.907Z","pid":1,"hostname":"94765fadf075","name":"EmailInbox","msg":"Error sending Email reply","err":{"type":"Error","message":"139802158573440:error:1408F10B:SSL routines:ssl3_get_record:wrong version number:../deps/openssl/openssl/ssl/record/ssl3_record.c:332:<br>","stack":"Error: 139802158573440:error:1408F10B:SSL routines:ssl3_get_record:wrong version number:../deps/openssl/openssl/ssl/record/ssl3_record.c:332:<br>","library":"SSL routines","function":"ssl3_get_record","reason":"wrong version number","code":"ESOCKET","command":"CONN"}} 

If I send an email directly to the inbox email, it shows up as a DM, but when I click it, it shows "Oops! Something went wrong. Please reload the page or contact an administrator."

My email is currently at AWS WorkMail. After some digging, I found this: https://docs.aws.amazon.com/workmail/latest/userguide/clients.html

Amazon WorkMail discontinued support for Transport Layer Security (TLS) 1.0 and 1.1. If you are using TLS 1.0 or 1.1, you must upgrade the TLS version to 1.2.

RocketChat is running behind a Caddy reverse proxy. Is the problem with my Caddy, or with RocketChat? Or is this a bug?