"SSL_read: cert already in hash table" when sending mail asynchronously
This was related to a Ruby concurrency issue fixed in a patch for version 2.3
Your logs suggests your app is running 2.0.0
. Updating the language version to at least the stable version of 2.3 would fix that problem. This can be easily done by changing your Gemfile
Ruby declaration:
ruby '2.3.8'