Job exception: getaddrinfo: Temporary failure in name resolution

Hello everyone, after adding CDN to my forum, I found that I couldn’t send emails. I’m not sure if it’s due to the forum or CDN issue. The error message is as shown above

/usr/local/lib/ruby/3.2.0/socket.rb:231:in `getaddrinfo'
/usr/local/lib/ruby/3.2.0/socket.rb:231:in `foreach'
/usr/local/lib/ruby/3.2.0/socket.rb:635:in `tcp'
net-smtp-0.3.3/lib/net/smtp.rb:643:in `tcp_socket'
net-smtp-0.3.3/lib/net/smtp.rb:656:in `do_start'
net-smtp-0.3.3/lib/net/smtp.rb:611:in `start'
mail-2.8.1/lib/mail/network/delivery_methods/smtp.rb:109:in `start_smtp_session'
mail-2.8.1/lib/mail/network/delivery_methods/smtp.rb:100:in `deliver!'
mail-2.8.1/lib/mail/message.rb:269:in `deliver!'
/usr/local/lib/ruby/3.2.0/delegate.rb:87:in `method_missing'
/var/www/discourse/lib/email/sender.rb:286:in `send'
/var/www/discourse/app/jobs/regular/user_email.rb:79:in `send_user_email'
/var/www/discourse/app/jobs/regular/user_email.rb:39:in `execute'
/var/www/discourse/plugins/chat/lib/chat/user_email_extension.rb:6:in `execute'
/var/www/discourse/app/jobs/base.rb:292:in `block (2 levels) in perform'
rails_multisite-5.0.0/lib/rails_multisite/connection_management.rb:82:in `with_connection'
/var/www/discourse/app/jobs/base.rb:279:in `block in perform'
/var/www/discourse/app/jobs/base.rb:275:in `each'
/var/www/discourse/app/jobs/base.rb:275:in `perform'
sidekiq-6.5.9/lib/sidekiq/processor.rb:202:in `execute_job'
sidekiq-6.5.9/lib/sidekiq/processor.rb:170:in `block (2 levels) in process'
sidekiq-6.5.9/lib/sidekiq/middleware/chain.rb:177:in `block in invoke'
/var/www/discourse/lib/sidekiq/pausable.rb:134:in `call'
sidekiq-6.5.9/lib/sidekiq/middleware/chain.rb:179:in `block in invoke'
sidekiq-6.5.9/lib/sidekiq/middleware/chain.rb:182:in `invoke'
sidekiq-6.5.9/lib/sidekiq/processor.rb:169:in `block in process'
sidekiq-6.5.9/lib/sidekiq/processor.rb:136:in `block (6 levels) in dispatch'
sidekiq-6.5.9/lib/sidekiq/job_retry.rb:113:in `local'
sidekiq-6.5.9/lib/sidekiq/processor.rb:135:in `block (5 levels) in dispatch'
sidekiq-6.5.9/lib/sidekiq.rb:44:in `block in <module:Sidekiq>'
sidekiq-6.5.9/lib/sidekiq/processor.rb:131:in `block (4 levels) in dispatch'
sidekiq-6.5.9/lib/sidekiq/processor.rb:263:in `stats'
sidekiq-6.5.9/lib/sidekiq/processor.rb:126:in `block (3 levels) in dispatch'
sidekiq-6.5.9/lib/sidekiq/job_logger.rb:13:in `call'
sidekiq-6.5.9/lib/sidekiq/processor.rb:125:in `block (2 levels) in dispatch'
sidekiq-6.5.9/lib/sidekiq/job_retry.rb:80:in `global'
sidekiq-6.5.9/lib/sidekiq/processor.rb:124:in `block in dispatch'
sidekiq-6.5.9/lib/sidekiq/job_logger.rb:39:in `prepare'
sidekiq-6.5.9/lib/sidekiq/processor.rb:123:in `dispatch'
sidekiq-6.5.9/lib/sidekiq/processor.rb:168:in `process'
sidekiq-6.5.9/lib/sidekiq/processor.rb:78:in `process_one'
sidekiq-6.5.9/lib/sidekiq/processor.rb:68:in `run'
sidekiq-6.5.9/lib/sidekiq/component.rb:8:in `watchdog'
sidekiq-6.5.9/lib/sidekiq/component.rb:17:in `block in safe_thread'

I can ping the SMTP server locally to connect

Sounds like it could be similar to this?