What changes were made to the Exchange server recently? You may simple need to restart the SQL Server service (with outlook closed if you are logged into the server) so that it can recreate all the connections to Exchange.
A reboot of the SQL Server may also be required.
Recover Data for SQL Server is a ‘savior’ that helps to rule out data
loss. This explicit application is codified with advance recovery
techniques that foster recovery of damaged, deleted or unusable SQL
supported MDF files. Special knowledge is not required to progress this
recovery software. The software successfully recovers stored procedures,
functions, indexes, constraints, reports, views, data types, tables,
triggers, and many more.