This error is typically caused by the aps.acf file.
The aps.acf file is generated by aADBConf.exe and contains the application’s database configuration details.
Follow the below to replace the file:
Exit out of Access APS.
Copy the aps.acf file from a working PC or a production environment where the application is functioning correctly.
Paste the copied aps.acf file into the corresponding directory on the affected machine, replacing the existing file if prompted.
Open file explorer and locate your aADBConf.exe file. Check the connection string and confirm that the server and database name is correct.
Open Access APS and open the Fee Earner console.