@Teri928 

See Section 14.3 in your router manual, ===> https://static.tp-link.com/upload/manual/2023/202304/20230428/1910013257_Archer%20AX1800_UG_REV1.20.0.pdf

Generally speaking, you'd restrict the DHCP from providing an IP Address to some set of addresses, as in the link above. Then you'd set the device to an IP Address OUTSIDE oif the DHCP possible assigned IP Addresses.

You could either assign the IP address you want for a device using the method described above, or in the PC itself under the Network adapter settings.

The reason for restricting the DHCP pool to be outside of the possible aassigned IP Address range is so that DHCP will NOT assign to a connecting device you one you set manually. If it did do that, that is assign the same IP Address to another device, your device would be disconnected.

It appeers that is what you did though?

So probably some screen captures might help, but if you did it as listed on the link, then are you at the latest f/w?

I'd contact Support (they basically are not here in the user-to-user forum) as it would be a serious bug.