Can't log into App store

[Shortcut]

Why do I keep getting this message when trying to sign in to App store on this Mac? I have the correct password and I can sign in on other devices. This is the message that I get: The data couldn’t be read because it isn’t in the correct format. app-store mac 10.14.

 

[honestone]

What exact Appel devices do you have?

Also, for any that are running Mojave, do you have the latest version of Mojave, OS 10.14.3?

 

[Shortcut]

What exact Appel devices do you have?

Also, for any that are running Mojave, do you have the latest version of Mojave, OS 10.14.3?

I have an I-phone, I-pad, Mac, and Mac Air. I am running Mojave, OS 10.14.3 on the Mac Air, and this is the one that will not allow me to sign in to the App store. No problem with the other three.

 

[honestone]

I also have an i-Pad, a mid 2017 Mac Book Air, and a late 2012 Mac Mini. Both of the Macs are running the latest version of Mojave, and I am having no issues at all "getting" to the App Store.

You state that it is the Mac Book Air that you are having an issue with, not your other Mac. How long is this been going on? Also, how did you "get to" Mojave on your Mac Book Air? Did you just upgrade "in place", or do a clean, fresh installation? What about on your other Mac?