'Class.function' doesn't exist in current context while using a self made NuGet Package

I have created a NuGet package on .NetCore class library and accessing it from another .net core class library. I can't call my public and static method from a public and static class even tho the class name is detected.
One point to make is that the Package works on a Console App properly. To create a package I went to property->Package->Create Package on build and also nuget.exe method. Both lead to the same thing

Can someone please help me out

This is the Nuget package code

This is the class library I'm calling the above package in