IServiceCollection’ does not contain a definition for ‘AddAutoMapper’

If we haven’t installed the package this is a mistake so, that the reason you are getting the error ‘IServiceCollection’ does not contain a definition for ‘AddAutoMapper’ and no accessible extension method ‘AddAutoMapper’ accepting a first argument of type ‘IServiceCollection’ could be found (are you missing a using directive or an assembly reference?). while installing the package to your application make sure you are correctly installing it to your API or the respective application/project () by selecting the default project in package manager console window

[ChrisWalshZX]

Current advice is that AddAutoMapper extension has been integrated into AutoMapper itself so no need for the extensions package.