Hi,

Please provide more information regarding the version(Old/New) of Episerver etc..

One more thing does it work if you set the optimizeCompilations setting to false in your website web.config?

 <compilation debug="true" targetFramework="4.6.2" optimizeCompilations="false" />

The cms was updated from 11.9.3 to 11.13.0 and commerce from 12.5.0 to 13.7.1.

Yeah it worked on setting optimizeCompilations to false. Is this the correct solution for this issue ?

If you set this property to false it will not optimize the compiled code files.

So I think instead of this you should try these things first.

1. Remove the "bin" and "obj" folder from your solution(all projects).
2. Clean the solution
3. Rebuild the solution.
4. If you are using the publish folder then please remove the "bin" folder from there as well.

If the above steps solve your problem then you are good. Otherwise, you can also try setting the defaultLanguage to C#

<compilation debug="true" defaultLanguage="c#" optimizeCompilations="true" targetFramework="4.6.1">

or try the different solution given here

https://stackoverflow.com/questions/18232549/no-owin-environment-item-was-found-in-the-context