Hello, I can't send a photo from the android file explorer to a rocket chat user

when I try to send a photo from Explorer, rocket chat informs me that it does not have access rights to the file storage, and does not offer to get them, there are no such extensions in the settings either. accordingly, I cannot send a file to users in the rocket chat, neither a photo nor a pdf/
But if I go into the rocket chat, and in the user’s chat I press +, then the photo will attach and go.
The hios v12.6.0 system is based on android, I tried it on poco smartphones there, too, does not leave the explorer.
(I don’t know the language, the translation is machine-made.)

how do I defeat this malfunction ?