Just a guess here but if you are not using soft water you may have a hard water scale coating on the sensor. The sensor is preventing the heating element from powering up because it thinks there is no water. Try filling the machine with vinegar for several hours (no more than overnight) This will dissolve hard water deposits and hopefully clear the sensor. (the sensor should be a simple continuity contact. If you can look inside and see a metal button and it is fouled clean it off.)
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Just a guess here but if you are not using soft water you may have a hard water scale coating on the sensor. The sensor is preventing the heating element from powering up because it thinks there is no water. Try filling the machine with vinegar for several hours (no more than overnight) This will dissolve hard water deposits and hopefully clear the sensor. (the sensor should be a simple continuity contact. If you can look inside and see a metal button and it is fouled clean it off.)