All my messages between 2017 and 2019 are missing!

[Rangor]

I have even tried restoring the messages from my previous phone (Note 8), but they do not restore to the conversation.

Why are they deleted?

[Samsung_specialist]

Hello,

What is the application where the conversation is saved? If it is from messaging app, then it can be transferred using smart switch.

[Rangor]

It is the messaging app, and I have in fact transferred everything using Smart Switch before this screenshot was taken. It seems that the messages either weren't transferred, or just disappeared.

I have tried all tranfer methods as well.