Can't connect to WiFi in the repeater mode

I want to connect router to the existing WiFi in the repeater mode. I am having constant issues with this. First, I was not able to connect to the existing 5G WiFi (although I can do it without any issues using my phone etc.) I get error "connection failed". After 10 times I was able to do it but I can see error message "Connected to the parent network, but the interface can't access the internet". After 10 minutes it started working, but later it just disconnected and I was not able to do connect again. After 1h of clicking "connect" I was able to connect again, but it is really annoying. I am facing the same issues in Beryl AX and in Flint 2. I have updated software, I also tried resetting the router. I was using android app for this. What can I do?

Can you try the following firmware. Helped me on the Beryl AX. Important: Start from scratch, don't keep your settings!

Beryl AX:
https://dl.gl-inet.com/release/router/rc/mt3000-open/4.6.3-op24

Flint 2:
https://dl.gl-inet.com/release/router/rc/mt6000-open/4.6.3-op24

Great, thanks. I will try this out