Usually synchronization should happen within 1-5 minutes at max (5 mins if there are lots of transactions) since Electron Cash is an SPV wallet and it only downloads the block headers. Here are a couple of things you may want to do:
1) Sometimes the synchronization gets stuck, it's safe to restart electron cash and let it retry the synchronization.
2) The server it's synchronizing from may be slow or few blocks back or down. Change the electron cash servers. You'll find a green / red icon towards the bottom right. Click on it and manually select a server from the server list (You may have to uncheck select servers automatically before doing this). After this,
3) Try to ensure that your PC firewall, network firewall or antivirus/antimalware aren't blocking electron cash from accessing the servers.
4) If all of these still doesn't work, I suggest going to the electroncash app-data folder and deleting the blockchain_headers file from there. Don't delete the wallets folder or files in it.
On Mac:
Open Finder
Go to folder (shift+cmd+G) and type ~/.electron-cash