Thanks for bringing this to our attention, leabuena01.
Let me share some information about this issue and route you in the right direction for support to help you fix this.
Upon checking here, the investigation about the error message you've encountered while turning on the Multi-currency feature has been marked as closed.
Please know that our team has already deployed a fix to this query. Since you're still experiencing the same error, I suggest contacting our QuickBooks Support Team so they can further sort this out and assist you promptly using their tools.
Here's how:
If you want to assign a foreign currency to your customer for future tasks, you can visit this article: Assign a foreign currency to a customer in QuickBooks Online.
Keep me posted if you have questions or concerns about multi-currency in QuickBooks Online. I'll be around for you. Keep safe always.
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