New Ring Doorbell Pro never used

I have had a new Ring Doorbell Pro just in package for 2 year and never used before. Yesterday I try to connect it but it just flash blue. I read on some forum and saw if it hasn’t been connected to power for a while it need to be charged. It sounds strange because it’s wired. Anyway I tried it and let i be power on and after around 2 hours it start to light up white. I click on the button and it was possible to connect it to my WiFi. Today when try to mount it I had to disconnect the power it was the same problem with flashing blue. I again wait for a couple of hours and success to connect it to wifi again. It works for a hours till it start to flash blue again. Now it send a error message about
“Your Device needs to be replaced.
Unfortunately, it looks like there’s an error with updating your device. Contact Ring Customer Support for further information and help with your security needs.”

Is this a known issue that if a Ring product hasn’t been connected for long time it can’t be used? Can the problem be if the unit has to old firmware?

Yes, even a wired device needs to have its backup battery charged before it works correctly. Likely leaving the doorbell alone for 24 hours would make sure the battery is charged before you proceed.
Its possible that the backup battery or something else is now faulty with the doorbell since it has sat around so long.
As we are just fellow users you’ll have to contact Support for any warranty or replacement options you may have.
Contact Us – Ring Help

Hi @user10857. The Ring Doorbell Pro does need to be connected to power for up to 8 hours before you can initiate setup. There is a capacitor in the Ring Pro that needs to be charged. Be sure to have your Pro Power Kit installed and that your transformer has the adequate voltage rating. This checklist here has great information.