this is really difficult to troubleshoot if you do not provide a URL with that website.
However looking at the source code it appears that there are additional target options you can select in your kantu editor. Look for the Target: field there should be a small arrow to click on to select other code selections to target the the button. Try the others, maybe that works.
“Targets”: [
“xpath=//*[@id=“root”]/div[3]/div[2]/div[2]/div/button/span/svg/g/rect”,
“css=#root > div.sc-dRZyXS.fpBpYr > div.sc-lnzCgU.hxIkZr > div:nth-child(2) > div > button > span > svg > g > rect:nth-child(1)”