Joe Exotic says the prison he’s in is shutting him off from the outside world, but officials there say it was nothing personal — the whole facility was on pause for a bit.

A rep for the Bureau of Prisons — the federal agency overseeing Joe’s new home in Fort Worth, TX — tells TMZ … all of their prison institutions went on a national lockdown last week in response to protests and riots breaking out.

While they were on lockdown, BOP says inmates temporarily had limited access to phones and email — but as of Monday, lockdown’s been lifted and everything’s pretty much the same as it was before.

In regards to letters Joe claims he hasn’t received — implying prison guards are keeping them from him, including potential mail from his hubby, Dillon — BOP flat-out denies that. We’re told even during lockdown, snail mail was being delivered to inmates like usual.

As we reported … Joe said Dillon had gone ice cold on him in terms of communication, but Dillon says he’d been sending letters, and is dismayed to hear Joe’s not getting them.

Now, BOP refused to comment on Joe’s specific living or medical conditions — which he described as hellish — for safety and privacy reasons.

Remember, Joe says he requires blood infusions every 4 weeks, but claims he hasn’t had one since January. He also darkly predicted he’ll be dead in 2-3 months.