Profile: Support

Nop team did a SQL script for upgrade nop 4.20 to nop 4.30.
You need to execute this script.

Execute this command

INSERT [MigrationVersionInfo] ([Version], [AppliedOn], [Description]) VALUES (637160666562551771, CAST(N'2020-03-18T07:23:31.000' AS DateTime), N'Nop.Data base schema')

Did you install the fresh nop 4.30 or upgrade the old nop instance?

Can you check if Migration table has the value?
Execute this command

select * from MigrationVersionInfo where [Description]='Nop.Data base schema'

Check the first string on this error message. You will see the name of the plugin with  the issue.
Nopcommerce 4.30 uses FluentMigrations and tries to install the plugin, but the old plugin doesn't have information about FluentMigrations.

What nopcommerce version do you use?
Nop 4.30?

Cloudflare is the proxy CDN. You needn't use this plugin

Download the new release and upgrade the plugin.
Overwrite new files and restart the nopcommerce instance.

Try the release 1.05

Thank you, I solved it in the release 1.29.

Please check your CSS styles with default theme.

Download the new release of the plugin. I did it today.
I wrote simple documentation.
[url=/documentation-nopimportmanager#q6]https://www.foxnetsoft.com/documentation-nopimportmanager#q6[/url]