If a PDF won't upload, the most common culprits are file size and browser cache. The free plan caps uploads at 100 MB — anything heavier gets rejected silently or causes a freeze. Clear your browser cache, try a different browser (Chrome tends to behave better than Firefox here), and make sure your internet connection isn't dropping packets mid-upload. Unstable Wi-Fi kills large file transfers reliably.
This usually happens with scanned PDFs or files that contain custom fonts. The converter can't extract what it can't read. Try flattening the PDF first using the 'Flatten' tool, then convert. If the output is still broken, the source file likely has encoding issues — re-export it from the original app before uploading.
A JavaScript error in the background is almost always the reason. Open DevTools (F12), check the Console tab for red errors, then hard-reload the page (Ctrl+Shift+R). If the freeze repeats, disable browser extensions one by one — ad blockers and script managers frequently interfere with the processing queue.
The download likely got interrupted. This happens when the connection drops during the final transfer step. Check your available disk space first — a full drive causes partial downloads that look complete. Re-run the task and use the direct download button rather than right-clicking to save.
Server-side queue overload during peak hours. Close the tab, wait 3–5 minutes, reopen the site and check 'My Files' — the processed document is often already there even though the progress bar never finished. If not, repeat the task during off-peak hours.