AdGuard on OW 22.03.2

Under AGH settings section for reverse DNS (rDNS) I have as setup via the uci script. The problem is that the button labeled "Test Upstreams" generates the following error message.

Server "": could not be used, please check that you've written it correctly.

Okay, only the part within quotes is listed in the Private reverse DNS servers field so Yes, it is written correctly.

Router is a Linksys EA8300 with lots of storage (45.8MB of free space remaining).

AGH passes the below test and otherwise seems to be doing its job.

dig +dnssec +multi @

Using OW's Ping tool I can successfully ping Static Leased host-names so not sure why the rDNS test button is generating the error.

I have the same problem. Did you manage to find the solution?