Give Lively have coded their Donation Widget in such a way that you can only place one per web page. (If you are interested in the technical reason, it is because they assign an HTML id attribute to the element that is used to attach the code. You cannot have more than one element with the same id on a webpage, which is why the second one cannot be used.)
To have more than one Donation Widget on your website, you'll need to place them on different pages. They document this in the Give Lively support guide entitled Use embeddable widgets to collect donations on your website.
I appreciate that's not what you wanted to hear but I hope this answers your question.
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