Support

It is possible that SiteGround's servers are blocking the transfer. Let's try the alternative site transfer.

First, make sure that you have deleted all Kickstart files from the target server.

Back on your source server, create a copy of your backup profile in the Profile page. Select the copied profile in the Control Panel page. Edit its Configuration.

Find the Archiver Engine row and click on Configure. Set the Part size for archive splitting to 10MB. 

Set the post-processing engine to Upload to remote FTP and click the Configure button next to it to set up the connection to your new server.

Under the post-processing engine there's the “Upload Kickstart to remote storage” option. Make sure it's checked.

Now take a backup with this profile. If it succeeds it will upload your backup archive (in up to 10MB files) and kickstart.php to the target server. You can then launch Kickstart on the target server to perform the restoration.

If it fails please ZIP and attach the backup log file so I can take a look and try to understand what's going on during the transfer.

You're welcome!

Now, let me go back and explain what I had in my mind and what I can deduce from the information you gave me.

You had previously told me that some files, namely the Kickstart files and a test file, had already been uploaded by the Site Transfer Wizard. However, the backup hadn't been uploaded. This told me that the upload via FTP or SFTP worked – at least for small files.

The error message you got was very vague but it made me think it's not the FTP/SFTP upload, it is the next step: Site Transfer Wizard trying to communicate with the new server over HTTP(S) to make sure that the (S)FTP path you gave it corresponds to the site URL you gave it. The only way for me to test that theory was to have you perform a known good upload of the entire backup archive over the same FTP / SFTP upload engine. Both the post-processing engine and the Site Transfer Wizard use the same FTP and SFTP upload engine. So asking you to use the post-processing instead of STW would give me the missing data point.

Since your upload through the post-processing engine works fine I can now tell you for sure that the problem is that when your SiteGround server tried to contact the Artera server over HTTP(S) the connection got firewalled and failed. This could be a firewall on either server and has nothing to do with FTP / SFTP.

Since the post-processing engine method works for you I recommend sticking with it instead of trying to get two hosts to figure out who's firewalling what :)

You're welcome!