I've seen a few threads on this forum regarding older browsers attempting to use http2 with banned ciphers. The TLDR is I don't believe I have any banned ciphers enabled.

Error message when my cert (garden variety Letsencrypt) is tested:

Chrome 49 / XP SP3

Server negotiated HTTP/2 with blacklisted suite

RSA 2048 (SHA256) | TLS 1.2 > h2 | TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA | ECDH secp256r1

Firefox 47 / Win 7 R

Server negotiated HTTP/2 with blacklisted suite

RSA 2048 (SHA256) | TLS 1.2 > h2 | TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA | ECDH secp256r1

My ciphers are listed at the bottom of this post (for clarity). What I did is list the enabled openssl ciphers and modified the output so there is one cipher per line (not shown here for brevity), then did a grep to look for AES256-CBC-SHA, which is the common term in both error messages. My search string is slightly different format than the error message, with the idea that it should match the openssl format. The only match follows:

grep -e AES256-CBC-SHA ciphers

PSK-AES256-CBC-SHA

Thus I don't believe I have enabled the banned ciphers.

Details:

Linux 3.10.0-693.11.1.el7.x86_64 #1 SMP Mon Dec 4 23:52:40 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

OpenSSL 1.0.2k-fips 26 Jan 2017

nginx -v

nginx version: nginx/1.12.2

openssl ciphers

ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DH-DSS-AES256-GCM-SHA384:DHE-DSS-AES256-GCM-SHA384:DH-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA256:DH-RSA-AES256-SHA256:DH-DSS-AES256-SHA256:DHE-RSA-AES256-SHA:DHE-DSS-AES256-SHA:DH-RSA-AES256-SHA:DH-DSS-AES256-SHA:DHE-RSA-CAMELLIA256-SHA:DHE-DSS-CAMELLIA256-SHA:DH-RSA-CAMELLIA256-SHA:DH-DSS-CAMELLIA256-SHA:ECDH-RSA-AES256-GCM-SHA384:ECDH-ECDSA-AES256-GCM-SHA384:ECDH-RSA-AES256-SHA384:ECDH-ECDSA-AES256-SHA384:ECDH-RSA-AES256-SHA:ECDH-ECDSA-AES256-SHA:AES256-GCM-SHA384:AES256-SHA256:AES256-SHA:CAMELLIA256-SHA:PSK-AES256-CBC-SHA:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:DH-DSS-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:DH-RSA-AES128-GCM-SHA256:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES128-SHA256:DHE-DSS-AES128-SHA256:DH-RSA-AES128-SHA256:DH-DSS-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA:DH-RSA-AES128-SHA:DH-DSS-AES128-SHA:DHE-RSA-SEED-SHA:DHE-DSS-SEED-SHA:DH-RSA-SEED-SHA:DH-DSS-SEED-SHA:DHE-RSA-CAMELLIA128-SHA:DHE-DSS-CAMELLIA128-SHA:DH-RSA-CAMELLIA128-SHA:DH-DSS-CAMELLIA128-SHA:ECDH-RSA-AES128-GCM-SHA256:ECDH-ECDSA-AES128-GCM-SHA256:ECDH-RSA-AES128-SHA256:ECDH-ECDSA-AES128-SHA256:ECDH-RSA-AES128-SHA:ECDH-ECDSA-AES128-SHA:AES128-GCM-SHA256:AES128-SHA256:AES128-SHA:SEED-SHA:CAMELLIA128-SHA:PSK-AES128-CBC-SHA:ECDHE-RSA-DES-CBC3-SHA:ECDHE-ECDSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:EDH-DSS-DES-CBC3-SHA:DH-RSA-DES-CBC3-SHA:DH-DSS-DES-CBC3-SHA:ECDH-RSA-DES-CBC3-SHA:ECDH-ECDSA-DES-CBC3-SHA:DES-CBC3-SHA:IDEA-CBC-SHA:PSK-3DES-EDE-CBC-SHA:KRB5-IDEA-CBC-SHA:KRB5-DES-CBC3-SHA:KRB5-IDEA-CBC-MD5:KRB5-DES-CBC3-MD5:ECDHE-RSA-RC4-SHA:ECDHE-ECDSA-RC4-SHA:ECDH-RSA-RC4-SHA:ECDH-ECDSA-RC4-SHA:RC4-SHA:RC4-MD5:PSK-RC4-SHA:KRB5-RC4-SHA:KRB5-RC4-MD5

all the cipher suites without GCM, CCM, or chacha20 are on the blacklist. 'AES256+EECDH' and 'AES256+EDH' both include blacklisted cipher suites.