German organization in Finland seeks contact management software

We are a German organization in Finland and are looking for contact management software, if possible combined with newsletter software.

We have the following requirements for the software:

• Management of contact data for members and external contacts
• Compliance with the European General Data Protection Regulation
• A web-based solution would be ideal
• The software must run on Windows and Mac
• A rental solution is desired; the software should run on a server in Germany
• Ideally, it should also be usable on mobile devices

Five software workstations are currently planned, with the possibility of slightly more in the future.