Hi, I am having the following problem:

Today Morning connection to SQL Server were working fine, but suddenly some users couldn't get connected, but the users that were already connected could still read and write data, their connection didn't get broken.

If i try too connect using SQL Server Authentication, I get the following error:

CryptoAPIfunction 'CryptAcquireContext' failed. Error 0x57: The parameter is incorrect.

If I try Windows Authentication, I get the following error:

Login faile for user '(null)'. Reason: Not associated with a trusted SQL Server connection.

The SQL Server Service is running with a Domain User, which Administrative rights.

At the begining sometimes you eventually get connected, but now anybody can connect, except the ones that were already connected.