The various SMTP plugins allow you to send emails from CF7 and WordPress in general, using SMTP (an alternative way of sending emails).
To use this you typically need to configure the SMTP plugin with your particular SMTP settings. If you don’t add these settings correctly you won’t be able to send emails via SMTP.
But it sounds like you don’t need SMTP.
If you deactivate your SMTP plugins, then CF7 and WordPress, will use the default phpmail method to send emails, which works fine for most people without any special configuration etc.
I’m guessing you may have read some of the numerous, uninformed comments in this forum that suggest that using a SMTP plugin is the solution that fixes all email sending & receiving issues. It definately isn’t and in many cases it makes things worse.
