Unable to claim server on Arch

I just installed plex-media-server-plexpass from AUR on my Arch install on my Raspberry PI 2. While the server starts fine and indexes my files, I am unable to claim my server on my Plex.tv account. I've run a Plex server on Windows 10 from this network previously without issue and I updated my firewall rules to point to my Linux box instead of my Windows box.

When I look at my Plex Media Server.log file, I see the following output from when I try to claim the server:

Feb 28, 2016 11:28:03 [0x6b6ff400] DEBUG - Request: [::1:45182] POST /myplex/claim?token=xxxxxxxxxxxxxxxxxxxxXujP7p (30 live) GZIP
Feb 28, 2016 11:28:03 [0x6b6ff400] DEBUG - HTTP requesting POST https://plex.tv/api/claim/exchange?token=xxxxxxxxxxxxxxxxxxxxXujP7p
Feb 28, 2016 11:28:04 [0x6b6ff400] DEBUG - MyPlex: Did token exchange for claim (returnCode: 403)
Feb 28, 2016 11:28:04 [0x6b6ff400] ERROR - XML: Entity: line 1: 
Feb 28, 2016 11:28:04 [0x6b6ff400] ERROR - XML: parser 
Feb 28, 2016 11:28:04 [0x6b6ff400] ERROR - XML: error : 
Feb 28, 2016 11:28:04 [0x6b6ff400] ERROR - XML: Start tag expected, '<' not found
Feb 28, 2016 11:28:04 [0x6b6ff400] ERROR - XML:  
Feb 28, 2016 11:28:04 [0x6b6ff400] ERROR - XML:  ^
Feb 28, 2016 11:28:04 [0x6b6ff400] ERROR - Error parsing content.
Feb 28, 2016 11:28:04 [0x6b6ff400] ERROR - MyPlex: Exception parsing XML:
Feb 28, 2016 11:28:04 [0x6b6ff400] DEBUG - MyPlex: Got a token poked, let's act on it.
Feb 28, 2016 11:28:04 [0x6b6ff400] DEBUG - Sync: onMyPlexSignOut
Feb 28, 2016 11:28:04 [0x726ff400] DEBUG - Completed: [::1:45182] POST /myplex/claim?token=xxxxxxxxxxxxxxxxxxxxXujP7p (30 live) GZIP 638ms 568 bytes 200 (pipelined: 5)
Feb 28, 2016 11:28:04 [0x6aeff400] DEBUG - Request: [::1:45182] GET / (30 live) GZIP
Feb 28, 2016 11:28:04 [0x6aeff400] DEBUG - Auth: We found auth token (xxxxxxxxxxxxxxxxxxxx), enabling token-based authentication.
Feb 28, 2016 11:28:04 [0x6eaff400] DEBUG - Auth: Refreshing tokens inside the token-based authentication filter.
Feb 28, 2016 11:28:04 [0x6aeff400] DEBUG - Auth: Refreshing tokens inside the token-based authentication filter.
Feb 28, 2016 11:28:04 [0x6aeff400] DEBUG - (Capabilities) Platform 'Chrome' not matched by plugin platform requirements
Feb 28, 2016 11:28:04 [0x6aeff400] DEBUG - It took 0.0 sec to serialize a list with 17 elements.
Feb 28, 2016 11:28:04 [0x6a6ff400] DEBUG - Request: [::1:45181] GET /myplex/account (30 live) GZIP
Feb 28, 2016 11:28:04 [0x6a6ff400] DEBUG - Auth: We found auth token (xxxxxxxxxxxxxxxxxxxx), enabling token-based authentication.
Feb 28, 2016 11:28:04 [0x6a6ff400] DEBUG - Auth: Refreshing tokens inside the token-based authentication filter.
Feb 28, 2016 11:28:04 [0x68eff400] DEBUG - Auth: Refreshing tokens inside the token-based authentication filter.
Feb 28, 2016 11:28:04 [0x726ff400] DEBUG - Completed: [::1:45182] GET / (30 live) GZIP 10ms 1021 bytes 200 (pipelined: 6)
Feb 28, 2016 11:28:04 [0x6aeff400] DEBUG - Request: [::1:45183] PUT /:/prefs?PublishServerOnPlexOnlineKey=true (30 live) GZIP
Feb 28, 2016 11:28:04 [0x6aeff400] DEBUG - Auth: We found auth token (xxxxxxxxxxxxxxxxxxxx), enabling token-based authentication.
Feb 28, 2016 11:28:04 [0x6aeff400] DEBUG - Auth: Refreshing tokens inside the token-based authentication filter.
Feb 28, 2016 11:28:04 [0x69eff400] DEBUG - Auth: Refreshing tokens inside the token-based authentication filter.
Feb 28, 2016 11:28:04 [0x71eff400] DEBUG - Completed: [::1:45181] GET /myplex/account (30 live) GZIP 9ms 495 bytes 200 (pipelined: 10)
Feb 28, 2016 11:28:04 [0x6aeff400] DEBUG - MyPlex: Toggling server publish state.
Feb 28, 2016 11:28:04 [0x71eff400] DEBUG - Completed: [::1:45183] PUT /:/prefs?PublishServerOnPlexOnlineKey=true (30 live) GZIP 13ms 231 bytes 200 (pipelined: 6)
Feb 28, 2016 11:28:04 [0x726ff400] DEBUG - WebSocket: client initiated close
Feb 28, 2016 11:28:04 [0x726ff400] DEBUG - WebSocket: processed 0 frame(s)
Feb 28, 2016 11:28:04 [0x726ff400] DEBUG - Removing notification stream because of close.
Feb 28, 2016 11:28:04 [0x71eff400] ERROR - handle_stream_read error 2 End of file
Feb 28, 2016 11:28:04 [0x6b6ff400] DEBUG - Request: [::1:45200] GET /:/websockets/notifications?X-Plex-Token=xxxxxxxxxxxxxxxxxxxx (30 live) GZIP
Feb 28, 2016 11:28:04 [0x6b6ff400] DEBUG - Auth: We found auth token (xxxxxxxxxxxxxxxxxxxx), enabling token-based authentication.
Feb 28, 2016 11:28:04 [0x69eff400] DEBUG - Auth: Refreshing tokens inside the token-based authentication filter.
Feb 28, 2016 11:28:04 [0x6b6ff400] DEBUG - Auth: Refreshing tokens inside the token-based authentication filter.
Feb 28, 2016 11:28:04 [0x6b6ff400] DEBUG - Creating a WebSocket for notification stream for account 1
Feb 28, 2016 11:28:04 [0x6b6ff400] DEBUG - WebSocket: Performing handshake from origin http://localhost:8888
Feb 28, 2016 11:28:04 [0x6b6ff400] DEBUG - Beginning read from WebSocket
Feb 28, 2016 11:28:04 [0x6a6ff400] DEBUG - Request: [::1:45183] GET /myplex/account (30 live) GZIP
Feb 28, 2016 11:28:04 [0x6a6ff400] DEBUG - Auth: We found auth token (xxxxxxxxxxxxxxxxxxxx), enabling token-based authentication.
Feb 28, 2016 11:28:04 [0x68eff400] DEBUG - Auth: Refreshing tokens inside the token-based authentication filter.
Feb 28, 2016 11:28:04 [0x6a6ff400] DEBUG - Auth: Refreshing tokens inside the token-based authentication filter.
Feb 28, 2016 11:28:04 [0x726ff400] DEBUG - Completed: [::1:45183] GET /myplex/account (30 live) GZIP 6ms 495 bytes 200 (pipelined: 7)
Feb 28, 2016 11:28:11 [0x6aeff400] DEBUG - Request: [::ffff:127.0.0.1:45619] GET /servers (27 live) GZIP
Feb 28, 2016 11:28:11 [0x6aeff400] DEBUG - It took 0.0 sec to serialize a list with 1 elements.
Feb 28, 2016 11:28:11 [0x726ff400] DEBUG - Completed: [::ffff:127.0.0.1:45619] GET /servers (27 live) GZIP 5ms 457 bytes 200
Feb 28, 2016 11:28:11 [0x6b6ff400] DEBUG - Request: [::ffff:192.168.2.135:41703] GET /library/sections (28 live) GZIP
Feb 28, 2016 11:28:11 [0x6b6ff400] DEBUG - It took 0.0 sec to serialize a list with 3 elements.
Feb 28, 2016 11:28:11 [0x726ff400] DEBUG - Completed: [::ffff:192.168.2.135:41703] GET /library/sections (28 live) GZIP 18ms 828 bytes 200
Feb 28, 2016 11:28:11 [0x6a6ff400] DEBUG - Request: [::ffff:192.168.2.135:41704] GET /channels/all (28 live) GZIP
Feb 28, 2016 11:28:11 [0x6a6ff400] DEBUG - It took 0.0 sec to serialize a list with 0 elements.
Feb 28, 2016 11:28:11 [0x726ff400] DEBUG - Completed: [::ffff:192.168.2.135:41704] GET /channels/all (28 live) GZIP 6ms 350 bytes 200

It appears that some XML response I am expecting from the server is instead returning a HTTP 403 or some other non-XML response. I enabled tokens in my logs so I could try to view the response coming back from the server, but trying to navigate to that URL produces a 404 page from Plex.tv.

Does anyone know how I can get this server claimed so that I can use it?

Arch iptables:

% sudo iptables -L INPUT
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     tcp  --  anywhere             anywhere             multiport dports 32400,32469,geniuslm,8324
ACCEPT     udp  --  anywhere             anywhere             multiport dports ssdp,mdns,32410,32412,32413,32414

Router port forwards: