With Arcgis Portal 10.6 after upgrading Chrome to version 89, webapps does not show popup when clicking on layers.
No javascript errors but popup are not displayed.
webapps continue working normally with Chrome 88 and with Edge/Firefox.
The No PopUp Info in Chrome post has verified that a cause for this is when the zoom setting in chrome is not at 100% - can you see if that is what is occurring?