Is there any add-on or plugin to connect with Cloud Service?

In order to attach large files, we should be able to provide a link with cloud services. Is the Pro version available with this feature, or is there an additional add-on for it?

eM Client does not support plugins and the Pro and Free License versions are the same in this regard.

The only option you have in eM Client is to notify you on send if the attachment exceeds a certain size.

Thanks. Would you let me ask one more question?
Whenever I tried to send a big file, “5.3.4 message size exceeds fixed maximum message size” error occurs.

Why does this happen? And is there something I can fix? 

Because the error begins with 5.3.4 this message is coming from your email server. Check with your provider and see what the biggest size is that they allow.

Also check (or know)  what the recipient’s provider will allow.
This isn’t a oneway affair…
The message may pass your email provider’s server, but be too large for the recipient’s email provider - hence no delivery…

eM Client has no limit on file attachment size (unlike MS Outlook) but if you are sending to and GMX, they are around the top of free email providers with 50MB per email. Gmail, Yahoo! and AOL are mid-range at 25MB per email. Zoho is among the worst with 12MB per email. These are both send or receive maximum sizes per message. Many like Microsoft servers (, Hotmail etc) and Zoho also have a limit of 10MB per individual file.

The default warning in eM Client is 10MB, and I think that is a good measure. If your attachment, or combined attachments are over that, consider a different way to send them unless you know that both your and the recipient’s servers can handle larger.