DMR EH50 will not record

My DVD recorder has recently started to give me the message that the discs i am using are incompatible and will not record.
The message ‘read only’ also appears
I am using DVD-R and DVD+R and both have previously worked
Can anyone help me please

Mine started to go after 3 months and reached the stage that it would not play normal DVDs.

I had the RAM drive replaced under warrantee and has been fine ever since