Welcome Petri to HDTimeline and hope I can help. I do not know if you have Domestic or International model HD...but if you have a SECURITY system, it may have automatically disabled the starting function, and may have drained the battery power down. Use an external slow charger for 24 hours and consider in the future using a Battery Tender when going away longer than a couple weeks. It sounds like if you only left it for a few weeks that it is probably a discharged battery
Check to see if your turn signals work and headlight work. Turn the bike so you can see the headlight (mirror, garage door or wall). Check if the headlight dims slightly or goes out when you try to start the bike. If it dims to 1/4 brightness or goes out, the battery is partially dead or has a bad cell. You will need at least 9-10V to power your ICM Ignition Control Module), and you should hear a slight "buzz or bump" sound as the EFI Fuel Pump "steers" and pressurizes. Try cleaning all the primary Battery cable wiring, at the battery frame, up to and including the starter. Check the fuses and terminals scrape and clean all contacts and connection and use dielectric grease to prevent corrosion. Hope this helps.