Hello ukanth,
Using 3.0.1 I have AFWall+ allowed for WiFi, LAN, Mobile, and in the logs if I try to Resolve Destination I can't, I get this reply;
Currently can not resolve Host for IP
However I can successfully ping the destination, so not sure why I can't Resolve it?
I've attached a LOGCAT
Thanks
Also using the Donate Key the Show hostname option does not work.
All the Host sections are empty in the logs, see the screen shot.

Have you whitelisted AFWall itself to connect to internet. If not it will not be able to resolve hostname.
@ukanth
Yes, I mentioned I allowed it for everything; WiFi, LAN, Mobile
Having the same issue. Running Oreo 8.1. Do not have the issue on my device running Nougat (7.1.2).
Same issue here. Oneplus 6T OS 9.0.7
Same here :
AFwall+ 3.0.1
LG G4 H815
MicroG for LineageOS 14.1
When I attempt to resolve manually, I get this message (always just ms):
Currently can not resolve Host for IP(151.101.0.133), timeout: 7 ms
Fixed, will be available in next version.