Not able to create Story/Bugs etc...

[Nirmala Muniyappa]

Error displayed when creating a Issue: We can't create this issue for you right now, it could be due to unsupported content you've entered into one or more of the issue fields. If this situation persists, contact your administrator as they'll be able to access more specific information in the log file

[Nic Brough -Adaptavist-]

Welcome to the Atlassian Community!

The most common reason for this happening is that you are using a MySQL back end database and it is not set up to support certain characters.  Your user may be trying to copy and paste, or somehow else insert and advanced emoji (the one I ran into first was the poop emoji).  

Check what they're trying to add to a text field does not contain anything clever like advanced emojis).