After connection through Calibre, Kobo reader can't do any syncs with Kobo itself

I've been trying to figure this out, but not having any joy.

I have a Kobo Touch (original), Aura (original) & Clara HD, all with the latest firmware and I've been finding that once I use Calibre to sideload books onto the devices, I'm unable to connect to the Kobo servers? Either by WiFi or by USB with Kobo desktop.

I actually did a little test the other day. My Aura had been loaded up with my kobo purchased books, then I added my sideloaded books. Not able to connect with Kobo, I then signed in and out of my account.

The upside to this was the ability to access Kobo again, the downside was that now a lot of the collections holding my sideloaded books were empty.

So I connected the Aura to Calibre, not to add/remove anything, but just for it to update the metadata for the sideloaded books. This part worked.
But once again I was unable to reach Kobos servers.

At the moment, I have the latest edition of Caibre, the Kobo extended plugin & kobo utilities installed.
I did try paring Calibre down & removed utilities & the extended plug in to see if that made a difference, but no joy. So I reinstalled them

Does anyone have any thoughts? Maybe I have a setting wrong in Calibre that's causing this or maybe its the Kobo firmware, I don't know.
But I wanna be selfish & have sideloaded books & connect to the Kobo servers at the same time ;)

Thanks in advance