Unable to create serializable iterator

[Allen12]

I am using a List Collector in a Catalog Item, when I do a For Each in Flow Designer I get this error "Unable to create serializable iterator for items:......". 

[Harsh Vardhan · Accepted solution]

Adding screenshot , this will help you. 

[Brian Sorensen]

This has helped me move the needle on something I am working on, but hitting a wall now
i am able to look up the multiple records now, but I then need to put them into an Entra ID group

I have it set to 
1. for each - Sys ID is one of record im looking up
2. look up each user in Entra ID

this is working, but then I can't add them to a group, it only adds the first record

any idea?

[Brian Sorensen]

got it! I couldn't see the add userS to group...