Hi  @raulet,

Does the problem occur only when the PCs are connected to the network? Are the PCs connected to the network by wired or wireless?

What are the specific models of the PCs?

Have you checked the settings of the PCs themselves?

Please connect the PCs to the guest network separately, and then connect other clients to the main network to see if the problem still exists?

Hi@raulet,

Please make sure you are tagging a TP-Link Admin (my account) if you want a timely response. Unless we are tagged we do not see that new responses have been added.  We do not subscribe to every thread, so rely on Tagging to ensure responses.  

Here are some suggestions for your issue:

• Analyze Network Topology – Check for potential loops, please also tell me the total number of connected devices.

For example:  Cable modem—router—main deco )))((( client devices

(Note: — stands for wired connection,)))((( stands for wireless connection )

• IP conflicts – Please set Address Reservation for critical devices.
• Verify Static IP Placement – Ensure existing static IPs are outside the DHCP pool and review DHCP settings.
• Disable QoS – Temporarily turn off QoS to rule out bandwidth prioritization issues.
• Check Access Control settings – Review is there an overly strict Access Control Lists 
• Adjust WiFi Channel – Change the Wi-Fi channel (e.g., switch to 1, 6, or 11 for 2.4GHz) to reduce interference.