Check that "IDM Integration Module" extension is enabled (arrow 4 on the image). If you use incognito mode in Chrome, you need to enable "Allow in incognito" checkbox (arrow 5 on the image).
3. I don't see "IDM Integration module" extension in the list of extensions in Chrome. How can I reinstall it back?
You need to open IDM installation folder ("C:Program FilesInternet Download Manager" by default, arrow 1 on the image), then drag and drop "IDMGCExt.crx" (arrow 2 on the image) file into "Extensions" page opened in your Chrome browser (arrow 3 on the image):