Konfigurasi SMTP error : Net::OpenTimeout (execution expired) pada Rails, etc

Ketika SMTP error timeout. Jika di Ruby/Rails seperti ini :

Net::OpenTimeout (execution expired): net/smtp.rb:539:in `initialize`

Penyebabnya karena secara default kebanyakan ISP port 25 / 587 diblokir.

Solusinya diganti pakai port 2525

Referensi:

• https://documentation.mailgun.com/en/latest/faqs.html#i-am-getting-timeouts-when-connecting-via-smtp-why