The recent two days I have received multiple

ALERT: PayPal Express Checkout Error () (28) SSL connection timeout errors

Anybody knows if PayPal is having problems with their servers? or it is the problem my site?

I recently installed the "Authorize.net (AIM)" module so I have disabled the "PayPal Website Payments Pro" payment module, "PayPal Express Checkout" is still enabled. Could this be causing the problem?