Impossible to share document with contactor..

Last week.

I initiated a meeting with a contractor. I created a bubble OK. Send the link to contractor OK .Contractor uses the web interface.

Conference start. Audio/Voice with contractor was great OK.

I wanted to share a document with contractor but the contractor never saw my document ...

I'm disappointed. Is it a proxy configuration issue ?

I have another meeting next week with the same contractor and I think I will be forced  to use teams ://

Best Regards,

Philippe THIRION