The URL Check was performed correctly. I inserted all the required info (transfer method SFTP) and copied and pasted the directory path right from Filezilla, with and without the ending slash.
I get the error
"Akeeba Backup cannot upload a test file called akeeba-16.png to your new site's root. Please check that you have entered the correct connection information and that it's possible for the FTP/SFTP user to write files into the directory you selected."
I tried to change the root directory permission from 775 to 777 with no success (cannot even connect in this case).
I remember that previously I performed the transfer successfully, on a different site but on same kind of servers on the same provider. But I cannot reconstruct what was different in that situation.
Can you please help?
Thanks
Marco