You should check your Daz log file to see what's going on in the background.
Click on Help -> Troubleshooting -> View Log file.
If you are using the 'Smart content' tab to apply poses, clothes etc. Clicking the check box 'Filter by context' will filter your content to show only those things that are compatible with the character you have selected in the viewport. As trying to apply Gen 9 poses to Gen 8 characters wont work.