Website is inaccessible: an error occurred on the server when processing the URL

Symptoms

• The following error appears when accessing example.com:

  An error occurred on the server when processing the URL. Please contact the system administrator.
  If you are the system administrator please click here to find out more about this error.

• After starting the Failed Requests Tracing in Plesk at Domains > example.com, the following traces can be found:
  

  D:VHOSTSEXAMPLE.COMHTTPDOCSDEFAULT.ASP
  LineNumber 17
  ErrorCode 800a0e7a
  Description Provider cannot be found. It may not be properly installed.
  FilePath D:VHOSTSEXAMPLE.COMHTTPDOCSFILE.ASP
  LineNumber 17
  CurrentStatement adoCon.Provider="Microsoft.Jet.OLEDB.4.0"
  SizeOfStatement 103

• Enable 32-bits application option is disabled under IIS > server_name > Application Pools > example.com > Advanced settings.

Cause

Incompatibility of the Microsoft.Jet.OLEDB.4.0 driver in 64 bit OS.

Resolution

1. Log in to Plesk;

2. Navigate to Domains > example.com > Hosting & DNS > Dedicated IIS Application Pool for Website
3. Enable Enable 32-bit applications option.