Access to the admin webpage

Fabc68 wrote:

I have a ReadyNas since 2012.

What model ReadyNAS do you own, and what firmware are you running?

The admin access issue is likely because your NAS doesn't support TLS 1.2 (which most browsers now require).  The workaround is to use FireFox, and set security.tls.version.min to 1 (browse to about:config and search for the setting).  There are some other things you might be able to do, but the details depends on the model and firmware.

Fabc68 wrote:

I am very close to buying a new NAS from Synology, but I guess I cannot just transfer the hard drives?

No, that won't work.  You can re-use the drives if they are healthy, but the data will be lost.   Note Synology has been locking their newest platforms to only accept Synology-branded drives.  They are in the process of reversing that, so be sure you are runnning DSM 7.3 (just released).

But if these are old drives, then you should consider getting new ones.  Likely you'd need fewer large ones - though if you don't have a large volume,  you could go with an NVME model (though I don't think Synology has a "pure" one at the moment, they do have some hybrid models with NVME slots).