Missing the DefaultProvider RegEx in the list of providers for UrlRewritingNet

Sometimes when trying to acess the site (admin or store) I get this error:

Can someone give me a light about this? I'm hosted at Softsyshosting.

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Server Error in '/' Application.

Missing the DefaultProvider RegEx in the list of providers for UrlRewritingNet

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ApplicationException: Missing the DefaultProvider RegEx in the list of providers for UrlRewritingNet

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
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