Troubles with a list workflow (SP 2010) in SharePoint 2013 (Office365)

Hi everyone,

I have been having issues with a list workflow (SharePoint 2010 workflow) in SharePoint 2013 online (Office365). That workflow is to update elements in the target list every time an element has changed in the source list. I managed to design this workflow if the element is of the field type text. Alas, the same workflow doesn´t work once the field type is of the sort “person or group” which I actually need (error message from workflow). Both data are of the type “person or group” (assigned to) and I have already made sure that all settings are equal. Any idea what the problem could be?

Thanks,

Mike