Yes, you can do that. Please refer to this guide for clear instructions.
A soft bounce indicates a temporary delivery issue of the campaign to an email address. This can be due to the email inbox being full, or the recipient mail server is experiencing some technical issues and is temporarily offline for example. In short this means the current campaign could not be currently delivered, but if you try again in the future you might be able to deliver the message because this is not a permanent delivery issue.
A hard bounce however means that there is a permanent issue with the delivery. This is due to email address not existing anymore for example or maybe the domain name of the recipient has expired...
Try to log out and log back in to your account and see if the issue persists. If it does please reach out to Vbout support.
When sending email campaigns, Vbout will only send the email once to the same contact. When importing a new list, Vbout will automatically detect duplicate contacts and import the same user only once.
Yes, Vbout allows you to use your own custom domain with your landing pages. Please refer to this guide for clear instructions.
Please refer to this guide for instructions on how to send a test email.