Same with me: "try again" later but logged in (?), errors code 530, 520, etc, slow search, slow opening pic's, slow opening lists of categories and locations, etc.
To speed things up I now use the button "upload" on top of the screen multiple times (right hand mouse click: open link in a new tab). In that way I can upload three in the same time as one during the slow periods.
But I also noticed the slow periods are not all the time, early morning (Netherlands) no problems. Maybe a backup-process or other site related maintenance during daytime?
On the "old website" sometimes there was sometimes the same problem: slow. But it turned out the receiving gate for the number of users was not enough: resulting in an overload.