Failed to authenticate on SMTP server with username "xxx" using 2 possible authenticators

I'm running Laravel 5.3 on PHP 7 with SwiftMailer 5.4.xx and I seem to be running into the subject error with an office365 account. Despite the numerous threads on how to resolve it I am still unsuccessful despite having the following

1. OpenSSL is enabled
2. I have a Valid SSL certificate
3. The user/ password is indeed correct
4. The SMTP settings are correct ( using port 587 with TLS)
5. The TLS versions are enabled and correct (1.2)

6. I currently do not have firewall

   I did a tes tusing testssl.sh software and got the following but not sure what this means....

   --starttls smtp smtp.office365.com:587

   Service set: STARTTLS via SMTP

   Testing protocols via sockets

   SSLv2 not offered (OK) SSLv3 not offered (OK) TLS 1 not offered TLS 1.1 not offered TLS 1.2 not offered TLS 1.3 not offered

Can anyone shed some light on it?

via Chebli Mohamed