How get the messages from user's mailbox on Exchange on-prem which enabled Hybrid Modern Authentication using oauth

Question

My target is get message from mailbox's user on Exchange on-prem using modern auth. It's coded by .Net framework.

I don't care we need to use ADFS or not. We can use any library/packages to support. We also enabled Hybrid Modern Auth. So we can use access token got from the application which created on Azure....

On Hybrid Modern Auth, I tried to use the access token got from the app on Azure Active Directory like this:

public static async Task<string> GetAccessTokenAsync()        
{                       
	string clientId = "8bf6e5f1-e994-4f29-b888-0456b8942***";            
	string secret = "6SF8Q~w.7LQgIYFyKSFdk4pXjCnbNnc1K5Jp****"; 
	string msDomain = "domain.onmicrosoft.com"; 
	
	IConfidentialClientApplication thisApp = 	ConfidentialClientApplicationBuilder.Create(clientId)                
	.WithClientSecret(secret)                               
	.WithAuthority($"https://login.windows.net/{msDomain}/")                
	.Build();           
AuthenticationResult accessToken = await thisApp.AcquireTokenForClient(new[] { $"https://outlook.office365.com/.default" }).ExecuteAsync();  

	return accessToken.AccessToken;       
 
}

Then use above access token to auth Exchange on-prem but got error "401 un-auth"

var accessToken = GetAccessTokenAsync().Result;
 ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2013);
 service.Url = new Uri("https://domain.com/EWS/Exchange.asmx"
service.Credentials = new OAuthCredentials(accessToken);
service.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.SmtpAddress, "******@domain.com");
Folder inbox = Folder.Bind(service, WellKnownFolderName.Inbox);

Do you guys have any ideas?