I've Been to Your Future

Both are about the ML in the future trying to prevent the FL's death in the past by connecting with her through her cellphone.

Both are mini dramas in which one of the leads can contact or travel to their school days through a phone, and attempt to save the other lead who died back then.

Both dramas are about one of the leads suddenly dying and the other attempting through time travel to save their life.

On the eve of college graduation, Ye Fan finally plucked up the courage to confess to Tao Tao, whom he had been secretly in love with for many years. However, Tao Tao died in an car accident, and the two were separated from each other. While packing up Tao Tao's belongings, Ye Fan accidentally obtained her old mobile phone and gained the ability to connect to the past. In order to save Tao Tao, Ye Fan decided to launch a time and space rescue.

Both jump between past and present as one of the leads in the present tries to change the past of their high school years and prevent the death of the other lead.

Both are about the ML in the future communicating with the FL in her school days in the past through a cell phone.

Both are short length fantasy dramas with the same actress and actor playing the leads.
...........................................

Both dramas involve one of the leads dying and then a cellphone allowing the other to return to the past/alter the events that happened. Both have a school setting.