I have a client reporting that they're unable to forward HTML emails, with or without attachments, when the message contains links to URLs. In my own testing, I've found that if the links are deleted from the email body before sending, all works as expected. Similarly, if I force using plain text for the email, the message sends successfully. My client is insistent upon using HTML email, and is insistent upon using Roundcube rather than an email client -Outlook, Thunderbird, etc.
When trying to send using HTML email while the message body has links, Roundcube will sit for a time, then put up a timeout error. This only happens when sending HTML email with links in the body. Switching to plain text or using an email client completely fixes the problem.
I'm hoping there's an obvious setting I can change to make this work again. My server is currently running the following:
Roundcube 1.4.11
DirectAdmin 1.62.4
CSF 14.10
Ubuntu 20.04 LTS
Thanks for your time