How to skip empty and missing values from a migration
It is difficult to help without seeing the structure of your source file (at least 1 sample record). But, here are some pointers:


At first glance, the error message says something about a source plugin exception. I believe the error might be stemming from the source plugin configuration.
The approach you are taking with skip on empty seems to be in the correct direction.
Depending on the data that the field contains, you might have to handle it differently. I usually add the following to debug exactly what is being received by a particular field process. Also, make sure that the value being sent to the migrate_lookup plugin is an array.


# ...
process:
  field_point_of_contact:
    - plugin: callback
      callable: print_r
      source: name
# ...



Have you tried removing the skip on empty part? I don't remember correctly, but migrate lookup might be skipping empty values by itself.
An array with empty strings is not considered empty. If your source provides values like [''], you might have to send the array through an array_filter() to remove empties.


I hope this helps. If it doesn't, you might want to share one row of fake data.