Uhttpd NET::ERR_CERT_INVALID

Google chrome is getting the NET::ERR_CERT_INVALID error when it tried to visit a lede router. Firefox connects without hitch. In addition the same google chrome can connect to an nginx server running on a raspberry pi 3 with the same certificate (with a different CN and alternate name, and different key, but all the optional data being the same.) This isn't a self-signed cert issue. The CA has been imported correctly as evidenced by the fact that chrome can deal with the nginx server just fine.

chrome: (Version 59.0.3071.109 (Official Build) (64-bit))
lede:(LEDE Reboot 17.01.2 r3435-65eec8bd5f / LuCI lede-17.01 branch (git-17.163.57307-c79bb96) )
router: (netgear 3700v4)
hostname uhttpd server: gw.wsrcc.com (ipv6-only) gets error
hostname nginx server: www.wsrcc.com (ipv6-only) works fine

(feel free to try to connect to either of the above for the purpose of solving this error).

One more thing, https://dev.ssllabs.com/ssltest/ likes both the uhttpd and the nginx ssl sites and flags no errors. So far I haven't figured out how to get chrome to give information about what it doesn't like about the uhttpd site.

It turns out that it had little do do with uhttpd. The problem was that google chrome is picky about the keyusage field including key encipherment, but only if the key is an RSA key. If it is an ecdsa key then key encipherment isn't needed. Nginx offered both the rsa and ecdsa certs so the lack of key encipherment wasn't an issue.