Domain Mapping plugin update 4.3.0.2 causing subsite login error

Domain Mapping plugin update 4.3.0.2 causing all subsites login to go to 404 error page denying login to dashboard. This involves only mapped domains for example domain-name.com as opposed to unmapped subsite domains such as main-site.com/domain-name/

This is rather an urgent issue as we have several hundred websites that cannot log into their dashboards to update their site so your swift response and hopefully solution is appreciated.

Regards,

James