Cannot import .xml form into workflow task

Hi All,
in the action "Start A Task Process" there is an option to import a form .nfp or .xml file.
For exported from other online workflows .nfp files it can be done succesfully. For downloaded from on-prem workflow .xml file it does not work. When I click on the Import nothing happens - it is stucked. In the Console there are some errors (see attached picture).
I have the same lists - which were migrated from onprem to online. 
Do you have any clue what could I do in that case? I have lots of forms to move and it would really help me.