The Situation
I have been using Calibre for some time now to generate a daily news collection with the fetch news feature. This feature is fantastic, and I have scheduled it to run daily and email the resulting book to my kindle, however for the program to run Calibre must be running on my host machine (obviously). However, I am traveling now and only have my laptop which is unable to be on 24/7. As such I have created an instance of Calibre running on a cloud hosted server to gather and send my news sources.
The Problem
I have configured the cloud instance of Calibre identically to instance on my laptop, using the export/import feature of Calibre. However, once the news is fetched Calibre emails the file with GMX to my kindle, but the email is blocked by Amazon. Amazon autoreplies to my GMX email the error message below, saying my “ip address is blacklisted”
Spoiler:
Exact Error Message
“This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of
its recipients. This is a permanent error.
The following address failed:
xxxxxxxx_kindle@kindle.com:
SMTP error from remote server for RCPT TO command, host: inbound-smtp.us-east-1.amazonaws.com (54.164.173.191) reason: 550 5.7.1 IP address blacklisted by recipient”
Troubleshooting- I believed that it could be a misconfiguration of the STMP settings in Calibre hosted in the cloud. However, given that GMX is receiving an autoreply from Amazon that would indicate that the email was sent.
- I checked my laptops installation of Calibre, verifying that the same GMX credentials and book were used, I successfully sent a book through GMX to Amazon.
- Both instances of Calibre return a success message when utilizing the “test email” function in Calibre
Conclusions
Taking that both instances of Calibre are configured the same way with the same credentials, I believe there is difference in the way the cloud instance communicates with GMX, which in turn communicates differently with Amazon’s servers.
If anyone has any idea on how I can get past this issue I would greatly appreciate hearing them.
General Info- The instance of Calibre in the cloud is running in a docker container using the image provided by linuxserver.io
- As far as I can tell the server instance of Calibre is the regular desktop instance running in kasm VNC
- The docker container is managed by me
- Access to the docker container is done via reverse-proxy to a url