docs: support verbiage for login issues (#947)

Added support verbiage for login issues due to several recent github issues being opened.

TROUBLESHOOTING.md

@@ -1,8 +1,9 @@
+If you have an issue logging into your Twilio SendGrid account, please read this [document](https://sendgrid.com/docs/ui/account-and-settings/troubleshooting-login/). For any questions regarding login issues, please contact our [support team](https://support.sendgrid.com).
+
 If you have a non-library Twilio SendGrid issue, please contact our [support team](https://support.sendgrid.com).
 
 If you can't find a solution below, please open an [issue](https://github.com/sendgrid/sendgrid-php/issues).
 
-
 ## Table of Contents
 
 - [Table of Contents](#table-of-contents)