This could be due to the following reasons:
- Connector is damaged
- Ethernet is not configured properly
- Ethernet card is malfunctioning
Apart from this, there are plenty of reasons for this issue. So, it's better if you could contact an internet service provider like network support Boca Raton by TheCompuLab if you want. You can get more information
here too. Or else you can try the method given below.
1. Update the network card driver.
2. If you are using any antivirus or firewall protection then turn them off.