When delivering surveys to recipients in an organisation where you have access to the email server you can elect to whitelist our email domains, this will ensure smooth delivery of surveys to your recipients on the email domain you control.
Sometimes in an office environment or on a controlled domain when delivering thousands of emails to members of an office your corporate email server will falsely mark the incoming emails as spam and some of your intended recipients will not receive their survey links, this is usually in an effort to protect your organisation from actual spam and scam emails.
By explicitly telling your mail server that you will be receiving communications from Tandem Surveys you can ensure smooth delivery in this setting.

Surveys on Tandem are sent from any of the following addresses;
If you are not the IT Administrator in your organisation, please refer this article to them and ask that the tandem surveys delivery domains be whitelisted for all inboxes within organisation.
For specific instructions on whitelisting email addresses and email domains in a corporate setting please refer to your mail servers administration guide and follow the process outlined for your mail server.
Please see the following guides for reference on common platforms