Not sure if you're having the problem still but I had similar problems. Implementing the below has given me problem free watching for over 3 months now.
I'm in the UK, using a Panasonic TV connected to an external WD Live media device which comes pre-loaded with the Slingbox app to connect remotely to a Slingbox Solo via a 30MB/2MB (download/upload) Virgin media internet connection. The Slingbox is connected to a Virgin Media SuperHub2 via TP Link extenders (data transferred via electrical wiring. Not the ideal set-up but irrelevant to the Error 27 problem I was experiencing. I was also suffering from disconnections after about 5 minutes when watching via the TV, no problems watching via the slingbox app on a Samsung tablet.
Spent about an hour via Live Chat with Slingbox Support a couple of weeks ago who were great and connected to my laptop to diagnose the disconnection issue. Here's what they did, may not solve the issues mentioned above as there may be something specific to everyone's individual set-up but this may help:
1. Make sure you have a static IP address (Mine kept changing)
2. Enable Port Forwarding using 5001. 5900 was also added as a test, it's still enabled so I can't confirm which port is actually the valid one. Suggest you try 5001 initially
3. This next step is key. It's not enough to just enable port forwarding, the Slingbox needs to be configured for internet viewing. Once you have set-up port forwarding go to this website, Slingbox - Country Selector log-in to your slingbox and follow the instructions. The test should go through the steps automatically and if successful the slingbox should be fully configured.
4. I also downgraded the default resolution (video streaming) for the WD device
I've not had any error 27 issues since Slingbox support did the above steps. It's vital that Step 3 is performed and changing the WD resolution has not noticeably impacted the playback quality. If you are trying to run the maximum resolution, the slingbox will try to optimize/compensate for the connection speed which can lead to the disconnections.
My view is that the Error 27 is just one of those generic error codes. Solving it meant making multiple changes, not just one, i.e. port forwarding.
Hopes this helps, it certainly solved my problems, I've not had an Error 27 since.
I run SlingPlayer on my iPad and it works fine. I run SlingPlayer on my iPhone/Roku and it works fine.
SlingPlayer on my NeoTV seems to be inherently unstable forcing me to restart the connection time and time again. I get a quick error code 27 or is goes black for a few seconds and then I get an error code 24.
I've seen a number of complaints but many go back to 2013, so I thought I'd start a new thread. Is this still a recurring problem for most people? Anyone have any ideas on how to fix this? I am unable to find anything written about this from Western Digital.