Storing API Response in Flutter - flutter

Question

I'm following an online trutorial to attempt to gain a better understanding of retreiving an API and storing it's response body to Hive.
In the online example i'm using i encounter an issue when attempting to store my response body. This is the error that i get;
Could any one give me any pointers to what i'm doing wrong?
My model
import 'package:hive_flutter/hive_flutter.dart';
part 'hive_solUser.g.dart';
#HiveType(typeId: 0) //, adapterName: "SolUserAdapter")
class GetSolUser {
#HiveField(0)
String? solUsername;
#HiveField(1)
bool? isUserActive;
#HiveField(2)
String? solSessionKey;
#HiveField(3)
String? firstame;
#HiveField(4)
String? lastName;
#HiveField(5)
int? id;
#HiveField(6)
String? email;
GetSolUser(
{required this.solUsername,
required this.isUserActive,
required this.solSessionKey,
required this.firstame,
required this.lastName,
required this.id,
required this.email});
GetSolUser.fromJson(Map<String, dynamic> json) {
solUsername = json['username'];
isUserActive = json['isUserActive'];
solSessionKey = json['solSessionKey'];
firstame = json['firstame'];
lastName = json['lastName'];
id = json['id'];
email = json['email'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = <String, dynamic>{};
data['username'] = solUsername;
data['isUserActive'] = isUserActive;
data['solSessionKey'] = solSessionKey;
data['firstame'] = firstame;
data['lastName'] = lastName;
data['id'] = id;
data['email'] = email;
return data;
}
}
API Service
class APIServiceSolUser {
Future<bool> getSolUser(BuildContext context) async {
log("Requesting Sol User List...");
var solUserListResponse = await HTTPHandler()
.httpRequest(url: solUserURL, method: RequestType.GET);
final response = await http.get(Uri.parse(solUserURL));
//final solUserListResponse = jsonDecode(response.body);
if (response.statusCode != 200) {
return false;
} else {
log("Sol User API RESPONSE SUCCESSFUL");
var data = json.decode(response.body);
var data1 = solUserListResponse;
List<GetSolUser> solUserList =
List.from(data1.map((users) => GetSolUser.fromJson(users)));
await GetSolUserProvider().updateSolUserData(solUserList);
await GetSolUserProvider().saveOfflineData(solUserList);
return true;
}
}
}