Orbea gain d50 error 33 help

[Anton11]

Hi, just joined, help please. I have a second hand 2 year old Orbea gain d50. Was working fine, now has an error 33, speed sensor problem. Have been trying to find info on line and in local cycle shops with little success. Nearest shop who say they can take a look (not necessarily fix) is miles away.
Any suggestions please or is this definitely a ‘need dealer’ issue.
Thanks in advance