@Dez Let me tell you the whole scenario. Firstly we should understand why this happening. Lets suppose a person submit a contact us form at your website and in return of that you mail the the particular person regards. Now by submit a contact us form user is not actually sending the mail and when you reply to customer, it will be first official talk between both of you, that was initiated by you.
Now what email filters thinking that you sending the email to unknown persons.
If you sending the mail using cpanel(shared hosting) or cpanel(vps) in these cases their will be more chances that your email will considered as spam email.
The reason of this is as follow:
- SPAM DETECTING FILTERS use ip address to detect the spam.
- Cpanel is not fully configured by using the standard configurations that should be their for sending the emails.
- In case of shared hosting, A lot of other customers also using the same ip for sending the emails that you using, If they doing spam in that case also your emails will also be considered as spammy email.
Look i am little bit agree with @ralphm that we can’t force emails. But in most of the cases the reason of spam emails are somewhere the mistakes done by us.
Sometimes what happen is when you are new to the market you emails will not be trusted by spam detecting filters, when you replying the form submit, but as the time go, they will find that you are the right person.
Look what my suggestions are:-
- After submit the form, don’t send the auto reply, send the email written by you.
- Don’t use the cpanel for sending the emails, use a email services provider company, that provider email for your custom domain.
I also suggest you don’t send the email for promotion purpose by using the same email id, that you using for communication with your clients.
Do these things, and i am sure it will work, If it will not work let me know we will solve it together.