Google does not have any control over how a third party system treats your messages. However, there are certain steps you could take to boost your domain’s spam reputation and prevent messages from being incorrectly marked as spam.
If you have not done so already, setting up a Sender Policy Framework (SPF) record is a good start in preventing Spam false positives. In an SPF record, you will list the sending IPs from which recipient servers can expect to receive your mail. By passing an SPF check, the recipient mail server is assuring that the origin of the message is legitimate and can be trusted.
The SPF record should read;
Host will be the @ symbol and the txt record value will be
v=spf1 include:_spf.google.com ~all
Should your domain use additional mail servers or sending I.P.s these will need to be entered into the SPF, your third party provider will be best contacted for the exact server information sending I.P ranges.
For more information about setting up an SPF record for your domain, see our Help Center article.
other option is to enable DKIM (DomainKeys Identified Mail standard) for your domain. DKIM authenticates messages and it allows the recipient mail server to determine whether or not key portions of the message, such as the from address, were not modified during transit. Passing a DKIM check assures the recipient mail server that the message was not tampered within transit, further boosting the spam reputation.
To generate your DKIM record you will need to;
- Sign into your Admin console
- Select Apps > G Suite > Gmail > Authenticate Email DKIM
- Click ‘Generate new record’
- Leave the prefix selector as ‘Google’ and select ‘Generate’.
- Copy the entire string of text provided and enter this as a TXT record within your domain’s DNS console.
- Once this has been saved fully within the domain’s DNS host come back to the Google Admin console, underneath the generated TXT record, select ‘Start Authentication’.
More information on configuring a DKIM record is available in this article.