Second monitor detected but not working

I have a PC with Ubuntu 22 and an NVIDIA Titan Xp GPU. The P used to run Ubuntu 16 and the dual monitor worked fine, but now it won't work (second screen remains black) even if the second monitor is detected:

I don't know if this is relevant, but I read the following error on dmesg:

[drm:nv_drm_master_set [nvidia_drm]] *ERROR* [nvidia-drm] [GPU ID 0x00000500] Failed to grab modeset ownership

This is the BIOS information:

BIOS Information        Vendor: American Megatrends Inc.        Version: 4001        Release Date: 05/28/2019        Address: 0xF0000        Runtime Size: 64 kB        ROM Size: 16 MB        Characteristics:                PCI is supported                APM is supported                BIOS is upgradeable                BIOS shadowing is allowed                Boot from CD is supported                Selectable boot is supported                BIOS ROM is socketed                EDD is supported                5.25"/1.2 MB floppy services are supported (int 13h)                3.5"/720 kB floppy services are supported (int 13h)                3.5"/2.88 MB floppy services are supported (int 13h)                Print screen service is supported (int 5h)                8042 keyboard services are supported (int 9h)                Serial services are supported (int 14h)                Printer services are supported (int 17h)                ACPI is supported                USB legacy is supported                BIOS boot specification is supported                Targeted content distribution is supported                UEFI is supported        BIOS Revision: 5.11

How can I fix this problem?