ParkMobile (a subsidiary of EasyPark Group from Sweden) is blocking devices that do not pass SafetyNet attestation in the following ways that I have discovered:
1) They block download of the app from the Play Store
2) If you install the APK by sideloading it, then when trying to login to a pre-existing account by email address or phone number, you will get the "Something went wrong" and "Forbidden" messages.
The level of attestation that they want extends to even devices running stock manufacturer firmware (unrooted) but with an unlocked bootloader.
This also extends to parking apps for specific municipalities that ParkMobile has branded with municipal branding, such as ParkBoston.
This can clearly be seen in the logcat logs for the app:
D unknown : LaunchDarklySdk: returning variation: {true,0,null} flagKey: feature_native_attestation_forcing_refresh_enabled context key: <redacted>
D unknown : LaunchDarklySdk: returning variation: {true,0,null} flagKey: feature_native_attestation_enabled context key: <redacted>
D unknown : LaunchDarklySdk: returning variation: {true,0,null} flagKey: feature_attest_reset_passwordless_enabled context key: <redacted>
I PlayCore: UID: [REDACTED] PID: [REDACTED] IntegrityService : requestIntegrityToken(IntegrityTokenRequest{nonce=<redacted>, cloudProjectNumber=<redacted>, network=null})
I PlayCore: UID: [REDACTED] PID: [REDACTED] IntegrityService : Initiate binding to the service.
I PlayCore: UID: [REDACTED] PID: [REDACTED] IntegrityService : ServiceConnectionImpl.onServiceConnected(ComponentInfo{com.android.vending/com.google.android.finsky.integrityservice.IntegrityService})
I PlayCore: UID: [REDACTED] PID: [REDACTED] IntegrityService : linkToDeath
I PlayCore: UID: [REDACTED] PID: [REDACTED] OnRequestIntegrityTokenCallback : onRequestIntegrityToken
I PlayCore: UID: [REDACTED] PID: [REDACTED] IntegrityService : Unbind from service.
D unknown : Error returned from API. code: 403 body: App attestation failed.