Fastmail eM Client caldav attachment just working one way

I’m using the eM Client 6.0.21040.0. In the overall the client is very fast and it’s covering most of the functions which are used daily at least in my case.
To my problem. I’m using Fastmail as e-mail service provider which also supports CalDAV (later on it will also support CardDAV but currently this is still in beta phase). When I’m adding a new appointement in eM Client then it it’s being replicated to Fastmail and I see it on the WebGUI as well. Vice versa is working as well. But if I’m doing the same with an attachment which I added to the an appointment within the eM Client then I don’t see that attachment in the WebGUI. If I’m adding an attachment on the WebGUI then I will see it on the eM Client. Therefore I assume that something is wrong with the eM Client. Let me know if you need further logs.

Hi Maurus, can you please try to update your client to this release and check if the issue persists, ?

Thank you,

I installed the newer version but the issue still exists (seen screenshot).
Adding a file on the web is seen in the eM Client => working.
Adding a file in the eM Client is not seen in the eM Client. => still not working also not with the newer version
Removing the file on the eM Client which was added over the web. => is working (maybe this info helps for troubleshooting)

Hi again Maurus, if you’re able to reproduce this issue, can you please navigate to Tools > Settings > Advanced and turn on CalDAV logging for the problematic account?

  1. Save the settings
  2. Restart the application
  3. Replicate the issue
    Once the issue reoccurs, please go back to the advanced settings window and click on “Send logs” and send the logs to my email with a reference link to this forum topic.

Thank you,

Reproduced the error and sent you the error logs as requested.

Just a short question. Do you happen to have already some results?

Hi Maurus, sorry for the belated reply, I’m sorry for the inconvenience, however it seems like this is a server issue, as based on the logs you’ve sent to us the file is being uploaded to the server without any error reports or issues, the file is attached to the calendar event.

Please check with your mail service provider as this might be a webmail/server issue.

Hope this helps,


As an additional check I created an event and I attached a file to the event on one PC over the eM Client. Then I checked the event on another PC over the eM Client and I could see there the attachment as well.

So it really seems a webmail/server issue. I will check that with the service provider.

Thank you, but please make sure to let us know in case you need our further assistance or you come across any other issues or questions about the application, we’ll be happy to help.


Will update you as soon I have some updates from the service provider.