Problems with FTP upload

Everything worked fine 2 days ago … but now I’ve competed the mobile device layout, it won’t upload … any ideas?

You need to provide a lot more detail for a better chance of a helpful answer. What do you mean with “won’t upload”? Can you provide a screenshot of the error?

Or would you try setting up publishing again? That generally surfaces the error in more clear terms.

Thanks Duncan and sorry about being vague. I was just wondering if there was a simple task I’d overlooked inbetween uploading the desktop version and then adding the mobile device layout. I’m guessing not, and I’ve not changed any of the settings at all.
It worked fine last Thursday, but now Sparkle is showing an error message: ‘The FTP server is not correct or blocked, please check whether the server address is correct’. The webhost has confirmed that there’s full connectivity at their end, and I’m running on ±65Mbps.
I can’t seem to fix it, despite renewing all the settings…

This can be tricky to diagnose, Sparkle is legitimately unable to connect to that FTP server, so there’s a networking issue somewhere.

The networking issue can be:

  • Locally on your Mac
    Your Mac can have network blocking software installed, for example TripMode is a popular app to reduce network usage when on tethered connections, and by default it blocks all apps on your Mac from connecting to the network. Others are Little Snitch, and antivirus software.

  • Between your Mac and your web host
    While you don’t typically think of anything going wrong between your Mac and some place on the internet, the FTP protocol has been recently abused by malware, and is targeted by network filters in general. Some ISPs will block FTP port 21 by default, if they do you need to ask them to unblock it.

  • On your web host
    While web host support will tell you everything is working, they often are not really interested in troubleshooting and solving the more obscure issues (low margin business, etc), and they usually don’t have visibility into the security features of their network. When the protocol is set in “autodetect” mode, Sparkle will connect to port 22 first (sftp) and 990 and 21 next (ftp implicit/explicit tls, plain ftp), and this in some cases triggers a “port scan” detection, so they will block your IP address. In other cases their FTP server is limited to a single connection, so if you have FileZilla/Cyberduck/Transmit open you can’t also connect with Sparkle at the same time.

So to address this, from simple to complex:

  • make sure you don’t have other FTP apps open on your Mac while trying to setup
  • make sure you don’t have network blocking software running on your Mac, or allow Sparkle to access the network/whitelist it in network blocking software
  • if your IP address is banned (hopefully only for a limited timespan) the above might be the solution, but you might still not be able to connect, this requires patience and maybe waiting a day and maybe bringing it up with the web host
  • if setup still fails, try using a mobile phone tethered connection to see if your ISP is blocking your FTP connection or your web host is blocking your ISP-assigned IP address

There’s no silver bullet unfortunately.


Duncan thank you - I’ve raised your points with the webhost, and run Sparkle again having closed everything else on the Mac - and all is fine, up and running.
Can’t thank you enough for this excellent app and first class customer service.