glitch in mail program io.3.9 / cant get into "sent"

[graypencil]

for some reason, my "sent " folder is totally grayed out and intermittently, with no rhytm or reason, I can't open any sent messages or move them to other folders.

I keep getting a message telling me the message I sent hasnt been downloaded from the server (?)

again ..this is an intermittent problem :

it existed this morning, but now I CAN access the sent mail

????