Hi Antonio,
The error that you are receiving is coming from your theme.
The theme is causing a conflict with WordPress itself. This may be due to migrating to a newer version of WordPress.
I would recommend contacting the theme developer and sending them this error.
Please could you also send us a copy of the migration restoration log? This can be found in the ‘wp-content/updraft’ directory of the new site via FTP.
The contents will be too long to post here directly, but you can use an online service such as Dropbox or Pastebin and post the link here.
Best Wishes,
David N