Sounds like an error caused by a ticking entity. A possible solution is removing your playerdata, which is what generally breaks first and causes this ticking problem. The playerdata contains mostly all player information, removing this will essentially make the player join as a new player. It will also reset your inventory.
Instructions:
1. Stop the server
2. Open your server files
3. Go to your world folder
4. Go to the playerdata folder
5. Use this lookup tool to find the UUID of your username, it will be a long string of letters and numbers
https://minecraft-techworld.com/uuid-lookup-tool
6. Delete the file that has the name of the UUID. If there are other files with the player name, removing them is generally not needed.
7. Start your server.
If the problem still happens you might want to delete all of the player's playerdata files, including the ones with the name of the player.
But if nothing above fixes it, you will need to restore a backup of the world, if you have one, or start a new world.