Incompatibility with usenet.premiumize.me

[ensisoft]

Server responds to the CAPABILITIES command with 400 instead of 500. Log below.

19:48:58:194 I Hostname resolved to 5.39.71.41
19:48:58:198 I Connecting to 5.39.71.41, 563
19:48:58:312 I Socket connection ready!
19:48:58:312 I Initializing NNTP session
19:48:58:312 I Enable gzip compress: False
19:48:58:312 I Enable pipelining: False
19:48:58:312 I 201 usenet.premiumize.me NNRP Service Ready - support@premiumize.me (no posting)
19:48:58:312 I CAPABILITIES
19:48:58:340 W 480 Authentication required for command
19:48:58:340 I AUTHINFO USER 5xxxxxxx
19:48:58:367 I 381 PASS required
19:48:58:367 I AUTHINFO PASS ****
19:48:58:401 I 281 Authentication accepted
19:48:58:401 I CAPABILITIES
19:48:58:882 E incorrect response code: 400 Unrecognized command