# ZXP timestamp signing -tsa **URL:** \ **Category:** Photoshop\ **Created:** [September 13, 2022, 1:48pm UTC](https://forums.creativeclouddeveloper.com/t/zxp-timestamp-signing-tsa/5232 "2022-09-13T13:48:54Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![TooL](https://avatars.discourse-cdn.com/v4/letter/t/df705f/32.png) [@TooL](https://forums.creativeclouddeveloper.com/u/TooL)\ **Post date:** [September 13, 2022, 1:48pm UTC](https://forums.creativeclouddeveloper.com/t/zxp-timestamp-signing-tsa/5232/1 "2022-09-13T13:48:54Z")
So I’ve just gone back to my old CEP extensions to get some boiler plate code and have found that I can no longer sign it with the `-tsa` flag. As per [Getting-Started-guides/Package Distribute Install at master · Adobe-CEP/Getting-Started-guides · GitHub](https://github.com/Adobe-CEP/Getting-Started-guides/tree/master/Package%20Distribute%20Install#use-zxpsigncmd-to-package-your-extension) I did used to use the `-tsa http://time.certum.pl/` as my tsa and that has worked for quite a few years after the geotrust one went down… Now I’m getting ```auto Error - the timestamp returned from the chosen TSA could not be verified, so the ZXP created is likely to be rejected by other tools. Please recreate your ZXP with a different trusted TSA. 35 ``` I’ve updated to the latest ZXPSignCmd.exe that I could find and have had no different outcome. Is there a currently working/accepted tsa to use or is there now a way to make it so the CEP HTML extensions work on other user machines? Cheers ---
**Author:** ![TooL](https://avatars.discourse-cdn.com/v4/letter/t/df705f/32.png) [@TooL](https://forums.creativeclouddeveloper.com/u/TooL)\ **Post date:** [September 13, 2022, 2:18pm UTC](https://forums.creativeclouddeveloper.com/t/zxp-timestamp-signing-tsa/5232/2 "2022-09-13T14:18:12Z")
After trying another …20+ timestamp urls I found one that works …for now from the github issue > > > Hey guys, > I was trying to sign a finished After Effects extension. > Followin…g the \[document recommended by this repo\](http://wwwimages.adobe.com/www.adobe.com/content/dam/acom/en/devnet/creativesuite/pdfs/SigningTechNote\_CC.pdf), > I was able to create a signed zxp package successfully, but when try to install the package using \[ZXPInstaller\](https://zxpinstaller.com/), I always get the same error "no valid signed certificate", and the installation fail. > If I do a validation on my zxp package using ZXPSignCmd, it outputs following messages: > \`\`\` > CN:'SeeShionTech' > OU: > DN: /C=CN/ST=HangZhou/O='SeeShionTech'/CN='SeeShionTech' > OS Trused=false > Timestamp:None > Sigining Certificate:Valid (form 2019-06-14 unti 2030-08-31) > \`\`\` > I'm using Windows 10, has you guys encountered such problem? [http://timestamp.digicert.com/](http://timestamp.digicert.com/) Hopefully this doesn’t go down too. ---
**Author:** ![Erin\_Finnegan](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.creativeclouddeveloper.com/erin_finnegan/32/100_2.png) [@Erin\_Finnegan](https://forums.creativeclouddeveloper.com/u/Erin_Finnegan)\ **Post date:** [September 14, 2022, 7:06pm UTC](https://forums.creativeclouddeveloper.com/t/zxp-timestamp-signing-tsa/5232/3 "2022-09-14T19:06:48Z")
They seem to go up and down all the time. 😟 ---
**Author:** ![TooL](https://avatars.discourse-cdn.com/v4/letter/t/df705f/32.png) [@TooL](https://forums.creativeclouddeveloper.com/u/TooL)\ **Post date:** [September 16, 2022, 2:03pm UTC](https://forums.creativeclouddeveloper.com/t/zxp-timestamp-signing-tsa/5232/4 "2022-09-16T14:03:23Z")
yeah…So I can get a list of ones that “seem to work” but the ZXPSignCmd seems to not like the result of. Such as the [http://time.certum.pl/](http://time.certum.pl/) …I encountered probably a good 10-15 that had that outcome and another 10-15 that were no longer available. Is there a chance that we can find out why? ---
**Author:** ![Erin\_Finnegan](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.creativeclouddeveloper.com/erin_finnegan/32/100_2.png) [@Erin\_Finnegan](https://forums.creativeclouddeveloper.com/u/Erin_Finnegan)\ **Post date:** [September 19, 2022, 8:45pm UTC](https://forums.creativeclouddeveloper.com/t/zxp-timestamp-signing-tsa/5232/5 "2022-09-19T20:45:39Z")
Wait, please list the ones that “seem to work” but are incompatible with ZXPSignCmd. I could the person maintaining the tool why some seem to work and some don’t, but I’m not sure they will know. ---
**Author:** ![TooL](https://avatars.discourse-cdn.com/v4/letter/t/df705f/32.png) [@TooL](https://forums.creativeclouddeveloper.com/u/TooL)\ **Post date:** [September 20, 2022, 9:24am UTC](https://forums.creativeclouddeveloper.com/t/zxp-timestamp-signing-tsa/5232/6 "2022-09-20T09:24:40Z")
I’ll see if I can find some time to get a list together. One for example is the above [http://time.certum.pl/](http://time.certum.pl/) which has worked for years. Also, would be good to maybe have a few from Adobe that can be put into the ZXPSignCmd.exe help info as it still lists ```auto options: -tsa - will attempt to timestamp the ZXP using supplied timestamp server. For example, https://timestamp.geotrust.com/tsa ``` which hasn’t worked for…at least what…5 years?