Error VM config File is too big

Hello, we use VM Explorer 6.2 and it`s working fine. But one Hyper-V Maschine could not backup up. It worked fine till last wekke and then Log brings the Error: "VM config File is too big". All other Vm were backup without Problems on the same Hyper-V Host (windows 2019).

How could we solve this error?  

Greetings

Peter