Error Message "Load Paper in Tray 1"

Dear all,

I'm french and having an HP 8725 since October 2018.

I have an issue since this morning. The printer was working fine, I was able to print 2 documents, then for the third one, I had the error 'Load Paper in Tray 1". Of course, I had enough paper. I tried to remove all the sheets and add new ones.

Still the error, I even don't hear the sound of loading sheets. I tried to reinitialized the parameters, I have still the issue.

I guess the issue should be the sensor to detect if sheets are there or not. But, I don't know what to do?

I'm stuck at home for Covid19 with 3 children, my wyfe is a teacher and as many people in this situation, we really need to use my printer everyday.

thanks for your help.