I am trying to use regex to find a string where ? could be between 0
and 10 characters, for instance the strings:

Error. Username 1092006871 does not exist. Record not processed.
Error. Username abc123 does not exist. Record not processed.
Error. Username does not exist. Record not processed.

would all yield results

However, the regex I am using:

Username ?????????? does not exist.

Gives a "Nested quantifier ?." error.

I have tried using *:

Username * does not exist.

but it doesn't find anything.

The only thing that seems to work is .:

Username .......... does not exist.

But that only matches on cases where the username is exactly 10
characters. I would like to match on cases where the username is
between 0 and 10.

Any help (and especially examples) appreciated.