Slow internet can be caused by a few different things, but the most likely culprits are:

1. High Volume of Network Traffic
2. Bandwidth Throttling
3. Signal Interference
4. Internet Service Provider Congestion

In order to troubleshoot this issue, the following steps should be taken:

1. Check Which Devices are Connected
2. Check your Router Settings
3. Use a Network Analyzer Tool
4. Run a Speed Test
5. Check for Signal Interference
6. Look for ISP Congestion