How can I send email through google security? - delphi

Question

I have developed an app for Android and iOS. I am using Delphi 10.2.3 Tokyo, with Indy 10.
I wrote a function for sending an email via Gmail with some help.
Although the function often works properly, sometimes it gets the error below when some participants log in Gmail with their own phones.
https://accounts.google.com/signIn/continue?sarp=1&scc=1sdf[...] Please log in via your web browser and then try again. Learn more at https://support.google.com/mail/answer/78754 y4-v6sm15938458pgy.18 - gsmtp
I have already seen Send e-mail using gmail and Indy, but I don't understand how I should use TIdSMTP.Password.
How should I revise my function to avoid this error?
The code is below.
type
TIdSMTPAccess = class(TIdSMTP)
end;
procedure MailSend;
var
IdSMTP: TIdSMTP;
Msg: TIdMessage;
begin
IdSMTP := TIdSMTP.Create(nil);
try
SSL := TIdSSLIOHandlerSocketOpenSSL.Create(IdSMTP);
IdSMTP.IOHandler := SSL;
IdSMTP.Host := 'smtp.gmail.com';
IdSMTP.Port := 587;
IdSMTP.Username := 'xxxx#gmail.com';
IdSMTP.Password := 'xxxx';
IdSMTP.UseTLS := utUseExplicitTLS;
TIdSMTPAccess(IdSMTP).IPVersion := Id_IPv6;
try
IdSMTP.Connect;
except
TIdSMTPAccess(IdSMTP).IPVersion := Id_IPv4;
try
IdSMTP.Connect;
except
// unable to connect!
Exit;
end;
end;
try
Msg := TIdMessage.Create(nil);
try
Msg.OnInitializeISO := IdMessage_InitializeISO;
Msg.ContentType := 'text/plain';
Msg.CharSet := 'UTF-8';
Msg.ContentTransferEncoding := 'BASE64'; // BASE64 (7bit)
//Msg.ContentTransferEncoding := '8bit'; // RAW(8bit)
Msg.From.Name := SsNoSt;
Msg.From.Address := 'xxxx#gmail.com';
Msg.Recipients.EMailAddresses := 'xxxx#gmail.com';
Msg.Subject := SsNoSt;
Msg.Body.Text := 'Unicode String (body)';
IdSMTP.Send(Msg);
finally
Msg.Free;
end;
finally
IdSMTP.Disconnect;
end;
finally
IdSMTP.Free;
end;
end;