Personal maps on Garmin UHD models do not work

[cladam]

Hello.
I just bought an Echomap 62 Dv UHD GPS and I can't see my custom chart that I've used for many years on older Garmin units. I get the legend "Unable to authenticate the map". Does anyone have a solution to this problem.
I will be very grateful for any help

[Boyd]

Unfortunately, I doubt that you'll find many (if any) members here with Garmin marine devices. But what exactly do you mean by "personal maps"? Did you create them yourself? If so, how? Or are they Garmin products that you purchased in the past?