First: does the Reel have sound on Instagram?
Open the Reel in the Instagram app with your volume up, and tap the speaker icon if it shows a muted symbol. If it is silent there too, the saved file will be silent too: the creator posted it without audio, or the soundtrack is licensed music that Instagram only plays inside the app. No downloader can add sound that the post doesn't carry.
The tool saved only the picture
Instagram stores many Reels as two separate streams, one for the video and one for the audio, and its own app joins them while you watch. A downloader that saves just the video stream gives you a clean but silent clip. This is the most common reason for a silent file, and it depends on the tool, not on you. Pullgrab detects this case and fetches a single MP4 with the sound included.
The file is in a format your player can't open
Some Reels come in a streaming-oriented format (VP9 video inside a fragmented MP4). The file is complete and undamaged, but a phone's default player or the Photos app may show a black screen, play nothing or refuse to open it. Pullgrab recognizes this format and retries to get a standard H.264 MP4 that every phone plays. If you got a file like this from another tool, open it in VLC (free, on every platform): it plays nearly everything.
Your phone is muted, or the app is the problem
Check the silent switch and the media volume, not just the ringer. On iPhone, the ring/silent switch and the volume in Control Center both matter; on Android, media volume is separate from ring volume. If the file plays with sound in one app and not in another, the file is fine and the player is the problem.
Still silent? A quick checklist
Paste the link again and download a fresh copy. Try the file in VLC. Make sure the Reel really has sound inside Instagram. If the original is silent in the Instagram app, that is the answer. Pullgrab never asks for your Instagram login and doesn't add a watermark.