SMTP Test Errors

I used my email credentials as suggested, but the testmails are not going through. I opened a ticket on this. They suggested that I contact my Hosting guys and I did. They had me do a test mail using smtp form the originating domain in question. That works.
I go back to try with your testmail and nothing. Please help as this is very frustrating!

https://ww.wp.xz.cn/plugins/visual-form-builder/