Hey nuked, Thanks for your quick replies and suggestions. I've been hitting my head on this issue for the past few days but only really been looking at the manual signing once clicking Distribute App after having created an Archive. Have just been playing with the Build Settings in XCode and settings section; I assume that I have had it wrongly set to code sign as iOS Developer. I changed that to iOS Distribution and set up the provisioning profile information there and re-archived. This now gets me passed the signing stage when I attempt to go through to Distribute App :) Ironically, as it's trying to upload Apple then complains as XCode 10 must be using SDK 12 which is unsupported as of June 2020.....so looks like I need to update my OS and XCode - oh joy!!! Long and short of it: I think the certificate issues was due to having had the Code Signing Identity field incorrectly set to iOS Developer rather than iOS Distribution and so when uploading a distribution version the app wasn't signed against the correct cert or something along those lines. Makes sense - just the error wasn't very clear. Thanks for your help/input!

Yep, it says the certificate is valid and I can see the linked private key. I created it fresh this evening to try again :) I've installed the WWDR certificate but not sure it's helping at all unfortunately. The documentation about using WWDR on an older version of XCode is lacking a bit of detail IMO :( If you’re unable to upgrade to a supporting version of macOS or Xcode on your build machine, you can build and archive your app using an earlier Xcode client and sign it for distribution using the latest release.

What version of XCode are you running? I've been switching between automatic and manual signing but each is complaining in the same way. I'm on XCode 10 and have got xcode to create the distribution certificate afresh but it complains that the private key isn't installed for some reason. When I go to my keychain though I can see the cert and linked private key. Under Manage Certificates in XCode I have a weird table with 2 rows: ____Certificate _____| _____Creator _____| ____ Date Created ____ |____ Status _____________| iOS Distribution ____| DeveloperName __|_______Today___________ | ____Not in Keychain ____| (This row is greyed out) iOS Distribution ____| ___________________|_______Today __________ | __________________________|

Did you manage to get a fix for this at all? I've been hitting the same issue this last week.

I've had this exact problem for the past 3 days with Xcode 10, going around in circles with automatic signing :( wish I had seen your post sooner!! Can you expand on how you manually signed your application? Did you create and download a provisioning profile or use the latest WWDR certificate? I've been trying to create a profile for the past hour, but it keeps complaining that there it does not include the selected signing certificate - which is definitely in my keychain. Appreciate any insights you might have!