Q:

RedisSessionStateProvider ERR unknown command 'EVAL'

When I run Microsoft. Web. Redis. RedisSessionStateProvider locally, I get the following error:
StackExchange. Redis. RedisServerException: ERR unknown command 'EVAL'

I have installed the latest RedisSessionStateProvider from nuget. 
Web config:
 <sessionState mode="Custom" customProvider="MySessionStateStore">
  <providers>

    <add name="MySessionStateStore" type="Microsoft. Web. Redis. RedisSessionStateProvider" host="" accessKey="" ssl="false" />
  </providers>
</sessionState>

A:

I was running a version of redis server pre 2.6. 
Quick easy way to get redis server for windows is via chocolatey. 
Install from here: https://chocolatey.org/
Then get redis using command from here:
https://chocolatey.org/packages/redis-64/3.0.501
Then go to C:\ProgramData\chocolatey\lib\redis-64 and run redis-server.exe
You'd then need to install as a service (see notes in C:\ProgramData\chocolatey\lib\redis-64)
OR just get a windows installer msi from here (even easier if you don't mind the version too much i.e. just for development) https://github.com/MSOpenTech/redis/releases

A:

You should upgrade your Redis as @SSED said.  You can download 32 bit version of redis here: 
https://github.com/cuiwenyuan/Redis-Windows-32bit
Also if there is another error "Active machine refused It" you should run redis-server.exe file after downloading it. 