Computer memory can fail and it usually causes reliability problems, unless ECC memory is used.
My preferred memory testing tool is: Memtest86+
Normal procedure is to test memory modules individually in different memory sockets, to identify the failing memory module or socket.
This entails reseating the memory modules. (Before handling memory modules please take anti-static precautions)
Modern memory buses use high frequency low voltage signals. They need a good electrical connection to work reliably.
Sometimes the process of reseating the memory modules can solve the problem, if it was caused by an electrical connection issue.
If memory tests continue to fail and the memory module is out of warranty, before replacing it you can try cleaning the contacts on the memory module for dust, dirt or corrosion.
I suggest using a piece of cloth with rubbing alcohol.
After cleaning, test the memory module again. If memory tests can run without errors for 24 hours, then the problem is likely fixed.