I ran the memtest-86, and it showed no errors, but just in case i swapped my ram-stick for a new one. Seems to be working so far, but only time will tell. Hopefully i wont return to this question later. Thanks for the answers!

Hello again!

To clarify, yes, I'm using Ubuntu 20.04.3 LTS, which should be supported. Also, by memory issue i didn't mean with the physical memory in my computer, rather, that there was an error with the software usage of ram, hence the error message linked to the free command. Although I'm not a professional programmer, so these opinions should be taken with heaps of salt. Anyways the ram on my computer seems to work fine, any other options?