Problem -- Nextcloud shares treated as spam and suspicious links

I’m trying out Nextcloud Provider Allsync. My team has not used Nextcloud before so I’m attempting to ease them in via Shared Folder links and OnlyOffice documents they can edit via email. I’ve begun sharing folders as r/w and password protected via email in two ways:

  1. Write an email from my own account and add URL’s for shared folders to it.
  2. Add each individual’s email under share folders settings within Nextcloud and assign permissions for each person.

I’ve run into some major issues and reported all of them directly to Allsync as well.

  1. Suspicious Links - Google hates them.
    Even with the personal email I wrote in step 1 above, the share URL’s show up as “Suspicious Links” so 7 out of 8 people refused to open them. My boss also stated there is no way we will use any suspicious service, so I sent a Google Drive link instead.

  2. Emails treated as Spam
    Each of the individual emails I sent out go directly to spam. I tested this with Gmail and others had the same experience.

  3. Formatting of email subject is terrible.

    user shared »Public Folder« with you

  4. Formatting of email body is terrible

Is this kind of formatting the default in Nextcloud? It is really bad! As mentioned above, I’ve reported all of this to Allsync + want to discuss it here as well. Guidance, feedback and suggestions greatly appreciated!

We even had this on the official Nextcloud demo servers. There are some reports about an unlisting process:

Spam filters of the big mail providers have very in-transparent filtering rules. Some should have some interface where you can analyse that. If it is your mail server, you can do certain things to reduce the risk of being recognized as spammer (reverse-dns entries, dkim signature, …).

The best is to report this on the bugtracker or even better submit a pull request to fix this issue :wink: It’s not unlikely that there is already a bug report, check out

For your mail to be liked by the big providers, you should implement valid DKIM signing, reverse DNS and make sure it passes SPF tests too. Gmail et al like valid DKIM signed messages.
The above should be enough in theory for them to accept your e-mails. At least for gmail, i’m not sure about i always see it as a chaotic mess.