Hello,
What string did you enter in the input box?
The accepted pattern is ^\s*[a-zA-Z_][a-zA-Z0-9_]*\s*,\s*[a-zA-Z]+(\s*,\s*[a-zA-Z_][a-zA-Z0-9_]*\s*,\s*[a-zA-Z]+\s*)*$. You can test your string against this pattern at: https://www.regextester.com/
This means that you are allowed to enter a name, followed by a comma and a ticker symbol, followed by more names and ticker symbols.
A name can have letters numbers and the underscore symbol. Same goes for the ticker.
So, if you want to introduce two coins, FooCoin and BarCoin, with tickers FOO and BAR respectively, you’d enter:
FooCoin,FOO,BarCoin,BAR
(In the upcoming wallets6 release it will be easy to create currencies via the admin editor, so this will become much easier.)
with regards