IOS – Can’t get Safenote to open; freezes on loading screen

Mine did this a couple times - I rebooted it (and left it off for about 15 minutes, although this doesn't make a difference in the real world I don't think) and the issue went away - although I presume you've tried this.

I'd try properly restoring the software back to non-jailbroken state (so you have fresh software entirely) and then (if necessary) re-jailbreaking it. Otherwise, depending on your model, restore back to vanilla setup and take it into the Apple store.

Found out the reason. I had a profile installed for an email account (that uses open-xchange servers) which was adding a Web Clip to the homepage. I disabled that Profile, and added the servers for the email account manually. Icon disappeared and problem solved! :)