Well, after all I decided to delete the original updraftplus and uploaded the new plugin-extension one.
Now, I create a key to migrate and then I write it down in the original site as It’s seen in the instructions. Unfortunately, the site says “Unexpected response: Error: Unexpected HTTP response code (503) (unexpected_http_code). You should check that the remote site is online, not firewalled, does not have security modules that may be blocking access, has UpdraftPlus version 2.10.3 or later active and that the keys have been entered correctly.”
I know I could download it from gdrive and upload it in the second site, but the backup is greater than 3GB and I can’t upload such files directly on my internet provider -this is the reason I paid for this plugin.
Please, what can I do? in the new site I don’t have any firewall installed. In the old, I use wordfence, but I don’t think this affects, does it?