To authorize Hostpoint to send emails on your behalf you will have to include it in your SPF record. The SPF record mechanism used by Hostpoint is shown below.

include:spf.mail.hostpoint.ch

For more information on SPF at Hostpoint, you can refer to their KB article below:

So far Hostpoint have not implemented support for DKIM signing outbound emails. However, for the latest information on DKIM please contact the Hostpoint support team.