Is one who lowers his gaze from women’s 'awrah (parts that must be covered) sinful if it appears to him unintentionally from another angle, and there is no way to avoid it except by covering his eyes or closing them?

It is obligatory for a Muslim to lower their gaze from what is forbidden to look at. However, it is not obligatory for them to close their eyes or refrain from walking in the streets. There is no sin upon them if they inadvertently see something, such as a woman, as long as they lower their gaze as much as they are able.