I have a 5-year-old Marantec 4500e Garage Door Opener . It always worked fine until a week ago. Now it suddenly will open but not close. It doesn't matter if it's operated using the remote or the wall mount button. The sensors are properly aligned and they are lit red and green solid. There are no broken springs and I oiled the track/rollers as well. When I unhook it and operate manually and then rehook, the door will open and close just fine again for a day or two and then the same thing will happen all over again. I have 8-1-2 lights blinking on the control module. I do not see this combination of errors in my manual! What is causing this and how can I fix it?

I recently lost my remote for my liftmaster 1155lm. In attempting to replace this remote I bought one at a big box store. While programing this new remote it seems that I have given access to my neighbors with their remotes. How do I erase this and or remedy my situation? Before you say hold the learn button until the led turns off... I've tried this and the led does not turn off while I hold it. I called customer service for lift master..... they could not assist since they don't service or troubleshoot products manufactured before 1993. Thanks in advance.