App Store "Cannot Connect to Store" after 10.13.4 update

No suggestions but I'm having the exact same issue on my MacBook Pro and my iMac. Hope the provide us with some kind of a fix. I'm still able to check for updates through the terminal though using softwareupdate -l

Thanks, good to know I am not alone. I hope there is a fix too. I will use the terminal method until there is a fix.

thanks for this, wait till the fix comes about...

how do you use the terminal method?

Paul

softwareupdate -l

I found the solution. It is in fact a security/permissions issue. Go to Keychain Access and open one by one all certificates marked with a blue plus sign. Change the trust settings to "Use System Defaults" and the blue plus sign should disappear. After you have no certificates with the blue plus sign, close keychain access and reopen App Store. It should work.

Yeah I found that solution online but it didn't work for me.

Make sure you do it in every item in keychain access with the blue cross (and you close key chain access). I first thought it was not working but then I found others in the bottom or not necessarily in the certificates section.

Nope, still no luck.

I can't connect either since updating to 10.13.4 b1. I've tried all the certificate and cache workarounds and it still won't connect.

At least $ softwareupdate -i -a still works.

Something new?

it still does not work and there is no proper solution.

if a new version or a fix comes now, I can not install it via the terminal.

And no, it is not a problem with the certificates or the contents of the folders.

I've already tried everything. This is the biggest bug I've experienced at Apple so far.

Ok, so may be it was not just the certificate fix but a combination what fixed my issue.

I did a clean install with thumb drive (and then restore from time machine backup) but the problem persisted. That is when I found the certificate fix by googling and it worked. I did not mention the clean install before because I thought that it did not solve it.

B2 didn't fix it for me but you can still update via Terminal using: $ softwareupdate -i -a

The 2nd version of B2 (17E150g) doesn't fix it for me either. Have tried all the things above except a clean install which I'm sure will fix it but for now sofwareupdate -i -a works so I'll limp along and hope this is something Apple will fix with some future update. I'm on a 2012 MacBook Air. My 2013 MacBook Pro works fine.

It does not seem to be a priority for Apple.

I have the same problem on two machines. On my (late 2013 iMac) I was able to update to beta 2 from the command line using

sudo softwareupdate -i -a

But after the update I have the same "Cannot connect to the Store. An internet connection is required" message when I open App Store. I have functioning wired and wireless connnections, and I am typing this from this very machine.

Now I will try the fix suggested by kcft above, "Change the trust settings to "Use System Defaults" and the blue plus sign should disappear."

Edit to add: OK, ultimately the "Change the trust settings..." worked, although it was tedious and I have no idea which certificte I changed that made the difference. Also, I am nervous about changing certificate settings when I really don't know what I'm doing. I suspect I actually only needed to change one or two of them, but I changed many. It would be good if someone could figure out the real culprit. There are two culprits --

1) Whatever caused the problem in the first place (for me, I think it was installing beta 1)

2) Which specific certificate(s) are borked, and what is the ideal fix.