Permissions for Project Online to access via REST api

dlafer Yes, we solved it after weeks of trying. We did this...

                ProjectContext myProjectContext = _projectOnlineUtils.GetProjectContext
                    (_configuration["ProjectOnline:SiteUrl"],
                    _configuration["AzureAd:ClientId"],
                    _configuration["ProjectOnline:PJOAccount"],
                    _configuration["ProjectOnline:PJOPassword"],
                    _configuration["AzureAd:TenantId"],
                    _configuration["ProjectOnline:Scope"]);

                ProjectCollection projects = myProjectContext.Projects;
                myProjectContext.Load(projects);
                await myProjectContext.ExecuteQueryAsync();

 and this

 public ProjectContext GetProjectContext(string siteUrl, string clientId, string userName, string password, string tenantId, string scope)
 {
     try
     {
         PublicClientApplicationBuilder pcaConfig = PublicClientApplicationBuilder.Create(clientId)
             .WithTenantId(tenantId);

         string redirectUri = "http://localhost";
         pcaConfig.WithRedirectUri(redirectUri);
         SecureString sc = new();
         foreach (char c in password) sc.AppendChar(c);

         AuthenticationResult tokenResult = pcaConfig.Build()
             .AcquireTokenByUsernamePassword
                 (new[] {scope},
                 userName,
                 sc)
             .ExecuteAsync()
             .Result;

         ProjectContext projectContext = new(siteUrl);
         projectContext.ExecutingWebRequest += delegate(object oSender, WebRequestEventArgs webRequestEventArgs) { webRequestEventArgs.WebRequestExecutor.RequestHeaders["Authorization"] = "Bearer " + tokenResult.AccessToken; };
         return projectContext;
     }
     catch (Exception e)
     {
         _logger.LogError($"{DateTime.UtcNow.ToString(CultureInfo.InvariantCulture)}: Error - {e.Message}");
         return null;
     }
 }

It need a bit of a clean, but it works.