The above error indicates that your PC has lost connection to the SQL server. Please note that maintaining this connection is the responsibility of the people in charge of your systems and network (rather than The Access Group), Therefore please refer this issue to the relevant people within your organisation. While we do not support this area directly, the below notes can assist in what to check and what could be affecting this.
Establishing who is affected will usually assist in tracking the area in your network that is causing the fault:
All users are affected -SQL or network issue
One user is affected - PC or network issue
SQL and network issues can include (but are not limited to)
SQL settings (such as automatically disconnecting users after a period of inactivity)
SQL server being unavailable on the network
Issues with the network DNS server
Issues with physical network (such as an issues with network routers)
PC and network issues can include (but are not limited to)
WiFi dropouts (note that is it recommend that PC's connecting to SQL server use a wired network connection
Issues with the physical network connection or cables
PC needs to be restarted following a Windows Update
ODBC connection on the system is set to connect to an SQL server using an IP address and the SQL server is setup to obtain an IP address via DHCP.
Please refer your issue to your internal IT team as they will need to establish what is causing your system to lose connection so that this can be rectified.