Guilin Sun
Ansys Employee

I thought you have resolved the issue. Sorry to reply late.

Error code 5 might be due to temporary server/license access issue. THis could happen when the network adaptor fails to work for some time due to uknown reasons; 

To isolate the cause, please change the optimization to sweep. If the sweep has the same error, then we can identify the file, and its settings as well as result matrix if any. You may try at least 5 simulation files at each generation.