The full text of this error reads:


Reported error is: Unable to cast object of type 'System.Collections.Generic.KeyValuePair`2[System.String,System.String]' to type 'System.String'.
at System.Linq.Enumerable.<CastIterator>d__97`1.MoveNext()
at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
at ZDChimpegration.MCListForm.PrepareSetupLog()
at ZDChimpegration.MCListForm.PrepareLog(String queryText, String queryName)
at ZDChimpegration.MCListForm.ProcessListsByQuery()


This error is unfortunately connected to a bug in version 4.10.0.3 and is affecting users who have GDPR settings available on their Mailchimp Audience.


There are two known workarounds:

1) Disable GDPR on the Mailchimp Audience (if you are not actively using these settings).  You can re-activate it when the fix for this bug is live (likely Q4 of 2021 - signup here to receive updates on Chimpegration versions). 



2) If there are any settings listed in the Available column when processing via Export (in the image below, you will see "Subscribed" in that column), you will get this error.

If all of the available preferences are moved over to the selected preferences, this will resolve the error.