Help Please - Unexpected error when launching Metadata Card Configuration

Dear Community,

I'm faced with the error below when launching metadata card configuration. The same error keeps popping up when relaunched.

Below is the full error stack:

TypeError: Unable to get property 'sourceType' of undefined or null reference
at SourceDefinition.assertSourceTypeDefined (/lib/json-conf-editor/io/defs/SourceDefinition.js:30:13)
at TextLoader.loadTextAsync (/lib/json-conf-editor/io/read-write/TextLoader.js:41:13)
at read (/lib/json-conf-editor/domains/MetadataCardDomainOnServer.js:67:21)
at DynamicSourceVaultMethodCaller.prototype.executeAsync (/lib/mfiles/helpers/DynamicSourceVaultMethodCaller.js:44:13)
at TextLoader.loaders.DynamicSourceDefinition (/lib/json-conf-editor/io/read-write/TextLoader.js:71:21)
at TextLoader.loadTextAsync (/lib/json-conf-editor/io/read-write/TextLoader.js:48:17)
at JsonConfiguration.loadSafeAsync (/lib/json-conf-editor/viewmodels/JsonConfiguration.js:129:13)
at JsonConfigurationDomain.prototype.getConfigurationAsync (/lib/json-conf-editor/viewmodels/JsonConfigurationDomain.js:672:13)
at DomainHeaderPanel.prototype.setDomain (/lib/json-conf-editor/controls/DomainHeaderPanel.js:67:21)
at JsonConfigurationDialog.prototype.setActiveDomain (/lib/json-conf-editor/controls/JsonConfigurationDialog.js:682:13)

Your help with resolving will be much appreciated. Thanks in anticipation.

Cheers!