IOS trial version register problem

I previously got the free unity version and registered it. However, I didn't select the 30 day ios trial and instead chose something like "free license" or so.. I was happy with the free version at the time, but I currently would like to use the IOS 30 day trial.. I tried reinstalling/redownloading the newest unity version (that comes with ios and android trial) form here but the register window no longer shows up and I cannot select the ios trial. When in unity I can't select the ios build (probably also couldn't with trial) and I don't think I can get the iphone developing layout etc. My question is: Can I get the ios trial although I previously downloaded/installed unity?

P.s: I know there are a lot of simialar questions but I couldn't find this exact case discussed on any of the other users. Could this perhaps help me? Any knowledge is warmly welcomed ;)