Error while migrating v4 to v5

I have setup a v5 server using docker

My existing v4 is updated to latest v4.

I initiated a migration from the v4 migration panel and specified the URL and Login (which matches the user on the v5 and v4).

I received the following email / error message:

Migration failed

Looks like something went wrong with the migration for the following company: [OBFUSCATED], LLC

                            Undefined variable $entity
                Undefined variable $entity

Note: The Obfuscation above is replaced with my actual company name.

Any direction would be greatly appreciated - thank you all!


Which specific versions of the v4/v5 apps are you using?