First of all, substitute the official files of SignalR SDK with the files that you can find at this link: https://github.com/eak65/FixedSignalRJar

When you do that, edit the "build.gradle" file of your application, adding the following code in the "android" block, after the "buildTypes" block:

    splits {
            abi {
                enable true
                reset()
                include 'x86', 'armeabi-v7a'
                universalApk true
            }
        }
    
    packagingOptions {
            exclude 'lib/getLibs.ps1'
            exclude 'lib/getLibs.sh'
            exclude 'lib/gson-2.2.2.jar'
        }

The above solution helped me after a lot of struggling! I hope it helps you too!

I have the same issue. Do I need to open .jar files and make some changes?