Session &1 could not be read.
&1 - The Session ID
A program needed information about the data for the current session.
However, the session data could not be read.
The error just indicates that a program could not read the session data.
As the message can be thrown by a number of API functions, which is available for
the developers - you should first check whether new programs using API functions
has been created. If this is the case you should check whether the input data
for the session surrogate is populated correctly.