The issue may be due to a wrong config register being configured on the ASA.PEerform the following steps to resolve the issue:
1)copy the existing config to a file in your computer.
2)Restore your ASA to factory defaults
3)copy the config from the file in your computer to the ASA and save the config.
5)perform copy-run-start.
4)Check that the default config register value is 0X1.
This will resolve the issue.