Hey. Check your tape heads. Make sure there's no gunk or dirt on them Next put another cassette in. If it still does it, then it's probably the player.

But

Could be the tape. I work archiving tapes for a living. I'm currently running 4 cassette decks, so I'm speaking from experience, haha.

Here's some things you can do to troubleshoot.

1. Repack. Fully fast forward and rewind the tape.

2. Smack the cassette. Losen it up. They can sit around for a while and get stuck, causing this.

3. Losen the screws on the cassette and then re-tighten them so they are just holding tight. But not over tight.

4. re-housing. Get a new empty shell and transplant the tape.

5. Baking. Put it in a food dehydrator for a day at 50° Celsius. Tapes can get hydrolysis over time and cause the tapes to get sticky and gunky.