I have encountered same error today. and i found that the image format was the issue. in my report i have used was causing the issue. so i have deleted the image and updated new image with .jpeg format and now the issue is resolved. please check if any image is cause the issue? and one more thing,

if you want to know what is the error please go to report server and check the log file.

you may find the proper error message as i did. any issue please let me know.

Dilip Chauha. dilipc01@gmail.com