Following the changes made by the Let’s Encrypt organization to their SSL/TLS certificates some users have reported problems with their email programs when connecting to Runbox’ email servers (see https://letsencrypt.org/docs/dst-root-ca-x3-expiration-september-2021/).
Therefore we are now replacing the Let’s Encrypt certificates for mail.runbox.com and related subdomains for IMAP, POP, and SMTP services to certificates issues by the Norwegian SSL certificate provider BuyPass.
This will standardize the certificates for all email service related domain names and gives wider support for various types and generations of email programs.
Note that if your email program is using a domain name not officially supported by Runbox it may stop working until you update your email program’s configuration to use mail.runbox.com as described here: https://help.runbox.com/email-program-settings/
In a transitional phase we will continue to support legacy domain names (specifically secure.runbox.com, imap.runbox.com, pop.runbox.com, and smtp.runbox.com), but we recommend that you change to mail.runbox.com now if you haven’t already done so.
UPDATE 2021-10-07: We have deployed an updated Extended Validation SSL certificate across our email service interfaces that resolves errors on incoming email related to TLSA records and DNSSEC for the domain name mx.runbox.com.