No it is not solved. I had to manually remove the repositories from /et kc/apt/sources.list.d/ whose GPG keys were missing. This seemed to be the error. This has prevented this from happening for me. However, it seems not to be an AppCenter as other Ubuntu users where experiencing it too.
No it is not solved. I had to manually remove the repositories from /et kc/apt/ sources. list.d/ whose GPG keys were missing. This seemed to be the error. This has prevented this from happening for me. However, it seems not to be an AppCenter as other Ubuntu users where experiencing it too.