At your end?
Check your internet connection, reset your router, check for any programs or services taking up a lot of your internet bandwidth.
Check cables (you could have loose connection or intermittent break in a network cable. If you have one, check your filter box (a lot of older (none fiber) internet setups require them & they can break randomly.
Over WiFi? Check for interference from other sources (some protocols are worse than others). Does your pc have a decent quality connection to it's router over WiFi? Is port forwarding required or is your firewall limiting network access for ED?
Wider:
Check with your ISP, are they having issues? Is there work or upgrading being done on their network. Are they throttling your internet connection for whatever reason?
In short, there are lots of reasons why it could be happening. Best that you can do realistically is reset your router, limit any other downloads and ensure that your firewall whitelists Elite Dangerous.