Hi @Wessel Van Erp ,
If you choose to use the auto-resolve Azure IR for both Source and Sink , which is the default,
For copy activity, ADF will make a best effort to automatically detect your sink data store's location, then use the IR in either the same region if available or the closest one in the same geography; if the sink data store's region is not detectable, IR in the data factory region as alternative is used.
For example, you have your factory created in East US,
When copy data to Azure Blob in West US, if ADF successfully detected that the Blob is in West US, copy activity is executed on IR in West US; if the region detection fails, copy activity is executed on IR in East US.
When copy data to Salesforce of which the region is not detectable, copy activity is executed on IR in East US.
For more clarification please refer to this doc : Integration runtime location
In case if your sink is also using Azure IR, I would recommend you to please try white-listing Sink data store region IP range, else try white-listing all the Azure IR Ip range
mentioned in the document. (Azure Integration Runtime IP addresses)
Hope this helps.
----------
Thank you
Please do consider to click on "Accept Answer" and "Upvote" on the post that helps you, as it can be beneficial to other community members.