warnings with index creation

I am copying a database to an online provider.
Copying the tables and the data was simple, however it does not create the extra indexes. So I run the sql script from the App_Data directory.

It gave me two warnings:

Warning! The maximum key length is 900 bytes. The index 'IX_Customer_Email' has maximum length of 2000 bytes. For some combination of large values, the insert/update operation will fail.
Warning! The maximum key length is 900 bytes. The index 'IX_Customer_Username' has maximum length of 2000 bytes. For some combination of large values, the insert/update operation will fail.


IS this a problem?