E-TAX-WEB-50008 problem: SPT SERVICE-00008, failed to generate BPE-Null which causes us to be unable to continue the tax invoice reporting process.
Generally this problem occurs when we do the upload process on the invoice site. There are several causes for this problem. Such as internet connection problems, invoice application versions that have not been updated, uploaded file formats that are not supported and several other causes of problems.
To fix this Etax-web-50008 problem, here are the repair solutions you can do:
1. File and Attachment Size Not Supported
The main cause of the Etax-web-50008 problem is due to the type and size of the file you are about to upload.
So, make sure you upload the attached file and the size is in accordance with the conditions that have been set.
2. Use Efficiency App V.3.0
As we already know, the efaktur version 2 is no longer supported, so like it or not you have to use the efaktur V. 3.0 application which you can download at the link below:

3. Use the latest version of the Efakur App
The efakur app has several update packages, if you are having problems with Etax-web-50008. Also make sure you have downloaded the latest invoice version.
4. Restart your PC/Laptop
It can also be triggered by network problems or system files on your PC/laptop, so try restarting your PC/Laptop first.
And after restarting try to repeat the upload process, is the error still there?
5. Wait a moment
If all of the above doesn’t work, there’s most likely a problem with the invoice server, so it’s best to wait a while.
Source : bacolah.com