The server resource pack will not download
Applies to the game client.
What it looks like in your log
Failed to download resource pack
What causes it
The client could not fetch or apply the server’s resource pack: a dead download link, a pack too large, or a hash mismatch.
How to fix it
If you run the server, re-upload the pack and update the URL and hash in server.properties. As a player, ask the server owner; it is not your machine.
Not sure this is your problem? Paste your log and Roastd will tell you which of these it actually matched, and what else it found.
Check your own log