Normally, the calendar iframe code looks something like this (it will be a different code for every church):
<iframe src="https://www.seraphimchms.com/integrations/calendarweb?cid=098098123-1208123-19023-as2130912sefjf&color=white&bckcolor=rgb(2,107,181)&sd=-20&ed=0-" width="100%"height="1150" seamless></iframe>
You’ll notice in the iframe above there is part of the link that should say “sd=-20&ed” …. Sometimes, when this code is copied and pasted, some browsers and sites will strip out the negative symbol, and will change it to “sd=20&ed” … The only difference is that small negative symbol. This is why your data is not appearing.
To fix the problem, all you should need to do is add the “-“ symbol in this one place “sd=-20&ed” then preview / save the page. Your data should then appear.