It’s important that you include the SPF/DKIM parameters in your DNS settings. SPF (Sender Policy Framework) is a DNS text entry which provides a list of servers that should be considered allowed to send emails for a specific domain.
The correct SPF would be – “v=spf1 a mx include:sendersrv.com ~all” .
The next step is the DKIM. Basically, DKIM attaches a ‘signature’ to the message in your emails. Not literally, of course – this ‘signature’ is in the code of the message itself. The DKIM has to be generated for you uniquely. We are developing a tool that automatically generates it for you in the system, but the current way to do that is to message firstname.lastname@example.org.
Once you receive the DKIM, include it in your DNS settings.
Also, Inbox settings sometimes play a large role in this – they may choose to filter out any non-business-related content(it sometimes might be the case with business inboxes). You should also avoid any illicit-sounding terms like “Male enhancement pills”, “Work from home”, “Make money instantly”, because they also might alert the inbox that you’re sending spam.