This is happening to thousands ... look at Apple Communities
https://discussions.apple.com/message/29949888#29949888
While Apple recognises and fixes bugs there are various suggestions in same site
One is, links into...
"URLs not working in Safari or Mail after iOS 9.2.1."
"URLs not working in Safari or Mail after iOS 9.2.1."
Update as of March 22, 2016: You'll see in community questions that hyperlink problem with 9.2.1 carries on and on, and Apple has not yet responded to the thousands of views ... One consequence is the freezing...
... u can unfreeze (power off button until u get screen w wipe question, then press Home until it clicks, kills the culprit app and unfreezes) and/or... substitute temporarily some of the main Apple culprits as follows...
My temp solution of substituting Mail by CloudMagic and Safari by Chrome works great >90% of the time. I complement w Mercury and , of course, Mail & Safari.
For linked problems w Calender i am using Fantastic.
I also changed VPN app/service to one with no hyperlinks so it doesn't freeze my app when changing some settings. Instead of XXX i now use TunnelBear and it works consistently.
This has taken the pressure off me and I'm relaxed using my iPad again!
it's a big pain erasing, resetting and attempting to recover from all the different backups, iCloud, Dropbox, etc etc and at the end there are no guarantees that solution will hold longer term.
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It's happening a lot with, it seems, the hyperlinking and affects Mail, Safari, etc seriously.
Some TEMPORARY solutions are in Apple's support communities :
https://discussions.apple.com/message/29949888#29949888
I just posted my "solution" in this forum thread and it is still working, about a month so far
Cheers and good luck!