Hi @Yehia, Asama ,
Welcome to Microsoft Q&A and thanks for posting your question here.
As I understand your query, you are experiencing error 'The data source credential had been deleted from current Integration Runtime node with payload' when trying to use lookup activity in ADF pipeline. Please let me know if the understanding is incorrect.
The issue here might be because the linked service underlying in the lookup activity is lacking the correct credentials or the linked service credentials don't have the required access.
Kindly check by clicking on 'test connection' in the linked service pointing to the datastore. If it's failing , Kindly create a new linked service with correct credentials again and use the same in the lookup activity.
If you still face issue, kindly provide more details like which datastore you are trying to connect to and since when are you facing the issue.
Hope it helps. Please consider accepting the answer if it's helpful as accepted answer helps community as well. Thankyou.