Error Step 3

Hi there, 
You can follow the workaround mentioned in this migration FAQs to fix that issue (please refer to the question in the FAQs: Q. Mage2Salesrule: Discount Qty is too long (maximum is 12 characters). 
If the issue still persists, please get back to us here. 
Regards,
Ubertheme team
 
 

Hi there,

Message: Mage2Attribute: Note is too long (maximum is 255 characters).

That issue because your M1 database has at least one record which has bad data in value of ‘note’ field in table eav_attribute.
You could run below SQL in M1 database to listing for that attribute at your end:

Select * From eav_attribute Where Length(note) > 255;

And then, you must fix the value of the note field in that records to decrease the length of value (<=255 characters)
Regards,
Mall.