Craftsman garage door remotes? Odd one! I have two remotes and two doors. I can cause...

Odd one! I have two remotes and two doors. I can cause either remote work for both doors but not at one and the same time. I can program one remote and try to program the second remote and get nil. I can clear the memory by holding down the learn buttons and program the remote that did not work fine but the one that did work past clearing momery, forget it. Each remote will hold the code for the openers but not at the same time. They both did work at equal time at one time. Does anyone have a clue.
How do I fix the problem of when...
Answers:    THEIR ON THE SAME FREQUENCY
Are the pipes getting blocked again?
To operation at same time you have need of 2 remotes ,each separately program near different cods .This mean you want two engine to this operation .(Each electromotive is open for one code program and as oodles remotes possible.Unless all remotes hold same code.Such as Car or hand remotes.