I can't write @ from VNC Viewer iOS 3.9.4

I can't write @ from VNC Viewer iOS 3.9.4 (iOS 15.1) to a VNC Server 6.8.0 (Ubuntu 20.04.3 LTS) Spanish (latín keyboard)

When I write @ it changes to the symbol ⅛
Instead of \ it is changed to the symbol `

Please help me solve this problem.
Thanks, greetings from Mexico