For solving my problem I’ve changed the following line
$per_page = 50;
in the “wp-content/plugins/youtube-video-importer/functions/admin/libs/channels-list-table.php” file, line #150.
On my opinion, It seems that the issue comes from the “page_token” parameter (line #158 of this file).
I think that the values to use from youtube API are nextPageToken and prevPageToken.
They are well retrieved and stored by the “_set_query_info” function but I could not found the code that should copy one of these values into the “page_token” parameter.
I hope it can help .