Microsoft.Jet.OLEDB.4.0 provider is not compatible with 64-bit machines,
you have 2 solution :
1/ Force iis to run the 32 bit applications : here's how to do it step by step with screenshots The 'Microsoft.Jet.OLEDB.4.0' provider is not registered on the local machine
2/ Migrate to a 64-bit compatible OLEDB Jet driver version :
download the Microsoft Access Database Engine 2010 Redistributable 64bits and update the connection string to “Provider=Microsoft.ACE.OLEDB.12.0;”
hope this helps.