When mwan3 active PXE do not receive ip address

Installing and Using OpenWrt Network and Wireless Configuration
1

When mwan3 active PXE do not receive ip address. If i stop mwan3 all work well. What could be the problem?

2

I assume PXE means preboot execution environment on a PC that is connected to a router that uses mwan3? If so, does it only affect the PC in PXE mode, or any device connected to the router?

3

I can not even boot through PXE. All device connected to the router work fine. When i start boot PXE, PC does not receive ip and show an error "No DHCP or proxyDHCP offers were received." . If i boot normal (through hdd) , dhcp work fine. If i stop mwna3 i can normal boot through PXE.