The data downloads are written to a directory which is set to be cleaned up from time to time. In the System Cleanup section, look for the Delete_Engine_Results task. I think it's set to 86400 seconds by default, that's 24 hours. If you set that to a higher value the files should be retained longer.

Thank you very much for your answer

What should I do! I can find is The System Maintenance as shown in figure:

I reset the time doesn't work,I didn't find Delete_Engine_Results task

Is that FME Server 2015? I don't have any of those around for checking.

Is there an option under the File Maintenance Tasks tab?

yes ! but the File Maintenanace Tasks tab is nothing ,The following figure

Check the cleanup service log, I believe it's located here:

<FME Server shared repo>\Resources\logs\service\current\<server>_fmecleanup.log

In particular, check for warnings and critical messages.

Thank you very much for your answer?

but I can't the useful information?This is my log of fmecleanup.log

this is fmecleanup.log all information ,Actually before is available for download ,But can't download now run results

The settings are probably not visible because your account does not have the required privileges. Can you check with an fme_admin account?

I am using the Admin account has all permissions ,

I think the reason is token, I have created the new token to the one month period, but still can't solve the problem

I see fmeEngineConfig log the default time is 3600 on the download URL was generated by FME Serve, but Ihave changed the FME_RESULT_LIFETIME to 0 (infinity)

Thank you for your answer

I look at the disk,the file exists,but download prompt the requested dataset has expired,please request it again to generate a new dataset avaliable for download,