Migration tool not working

Oh dear, oh dear. I’m sorry that your rollout of MailPoet 3 hasn’t quite gone as you would have liked.

It certainly hasn’t worked for me – but I’m not going to run off and write a horrible review like those petulant sponges who demand everything to be five-star AND FREE!

Anyway, I upgraded one site without any problems. However, when I tried to do the same on another very similarly configured site on the same server with the same browser, the problems began.

Firstly, the ‘Start Upgrade’ button did nothing when clicked. So I copied the console log (pasted below). After a while of trying, I opted to go straight to the Settings to try to Install from Scratch, however, only the tabs were visible on the Settings page, with no settings content below.

Do you think you can help? I’m very happy to provide more information if you need it.

Many thanks,

Chris

MailPoet Version 3.4.4
WordPress Version 4.9.4
PHP Version 5.6.33 (with PDO, PDO_MYSQL, XML and ZIP)

CONSOLE LOG:

admin.php?page=mailpoet-migration&mailpoet_redirect=https%3A%2F%2FDOMAIN_REMOVED%2Fwp-admin%2Fadmin.php%3Fpage%3Dmailpoet-newsletters:181 Uncaught ReferenceError: ZeroClipboard is not defined
    at HTMLDocument.<anonymous> (admin.php?page=mailpoet-migration&mailpoet_redirect=https%3A%2F%2FDOMAIN_REMOVED%2Fwp-admin%2Fadmin.php%3Fpage%3Dmailpoet-newsletters:181)
    at i (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:2)
    at Object.fireWith [as resolveWith] (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:2)
    at Function.ready (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:2)
    at HTMLDocument.K (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:2)
(anonymous) @ admin.php?page=mailpoet-migration&mailpoet_redirect=https%3A%2F%2FDOMAIN_REMOVED%2Fwp-admin%2Fadmin.php%3Fpage%3Dmailpoet-newsletters:181
i @ load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:2
fireWith @ load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:2
ready @ load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:2
K @ load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:2
load-scripts.php?c=1&load[]=hoverIntent,common,admin-bar,svg-painter,heartbeat,wp-auth-check,jquery-ui-core,jquery-ui-widget,jquery-ui-progressbar&ver=4.9.4:246 Uncaught TypeError: Cannot read property 'hasClass' of undefined
    at HTMLDocument.<anonymous> (load-scripts.php?c=1&load[]=hoverIntent,common,admin-bar,svg-painter,heartbeat,wp-auth-check,jquery-ui-core,jquery-ui-widget,jquery-ui-progressbar&ver=4.9.4:246)
    at HTMLDocument.dispatch (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:3)
    at HTMLDocument.r.handle (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:3)
    at Object.trigger (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:3)
    at Object.a.event.trigger (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:9)
    at HTMLDocument.<anonymous> (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:3)
    at Function.each (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:2)
    at a.fn.init.each (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:2)
    at a.fn.init.trigger (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils&ver=4.9.4:3)
    at Object.<anonymous> (load-scripts.php?c=1&load[]=hoverIntent,common,admin-bar,svg-painter,heartbeat,wp-auth-check,jquery-ui-core,jquery-ui-widget,jquery-ui-progressbar&ver=4.9.4:245)