FEED just stopped working when changed permalink

Hi,

I have changed my permalink status from

https://www.justcreativedesign.com/index.php/feed

to just

https://www.justcreativedesign.com/feed

and now my feed doesn’t work.
Since I have changed my permalinks, I can’t get it to work on the old or the new address… Please click on the links above to read the error messages I get.

When I try to change the links in feedburner settings it says:
“Error on line 4: The markup in the document following the root element must be well-formed.”

What am i doing wrong? Thanks.
Jacob