ionic tag is not working in ionic App…only HTML tags are supported
What errors are you getting. Can you share sample code
no error is occurring…but when I’m using ionic tags that time I can’t get the output 
Have you updated your ionic CLI?
$npm install -g ionic
If that does not work, then
You have to share some code via codepen or plunkr
Better: You have to share anything with us so we know what you are doing, what you are expecting and what is happening instead. Please also post the output of ionic info and your package.json so we know what software we are dealing with.