The error message "Can't find custom codec. Please use version 1.49.0 ARMv8 NEON codec." is a version mismatch error.
files or newer "All-in-One" (AIO) packs that cover all architectures. Version 1.49.0 ARMv8 NEON : Specifically used for newer 64-bit Android devices. AIO ZIP (Recommended) mx_aio.zip mx player custom codec 149 0 armv8 neon
What it does
Check the version number. If it matches the series, you need the 149.0 codec package. The error message "Can't find custom codec