Check whether you are filling in a correct phone number i.e., the one you used for downloading your certificate or the one you used for previous registration. It is important that your insurance number and phone number are combined in a way the system already knows. If you are not sure which phone number to use or if the problem is still persisting, contact the 1221 hotline. Please note that some vaccine types require a longer timespan between single doses than 3 months, for more information please see the Information about available vaccines Life Situation page.