Hi @lowlandet,
Seems something is added whitespaces to the responses, and the requests are halted right away.

Please add the following code to your wp-config.php for debug setup.
And please inform us of the issues for further support.
// Enable WP_DEBUG mode
define( 'WP_DEBUG', true );
// Enable Debug logging to the /wp-content/debug.log file
define( 'WP_DEBUG_LOG', true );
// Disable display of errors and warnings
define( 'WP_DEBUG_DISPLAY', false );
//SET PHP INI DISPLAY ERROR FALSE
@ini_set( 'display_errors', 0 );
Please find the video will help you to edit wp-config.php and add the above code: https://www.youtube.com/watch?v=3SDPTafEM8o
If that does not help, please provide the following details in the secure note:
– FTP or CPanel Credentials
Thanks