Our data indicates NoSpamProxy supports full DMARC compliance.
Contact NoSpamProxy for DKIM setup.
There are two suggested includes - 'include:_spf.nospamproxy.com' and 'include:spf.servicemail24.de', however this most likely broadens the list of authorized servers beyond what you need. Before making changes to your SPF, be sure to contact NoSpamProxy and verify if there's a more customized list of servers they can provide. More information is also available here: https://www.nospamproxy.de/de/spf-authentifizierte-server-in-e-mail-server-des-unternehmens-eintragen/