I get that too, so some others of us are protected. I’m running Firefox on my Windows laptop.
Turning into a quite regular thing. Bursty. No problem for 20 or so threads/posts and then blammo. Nothing works for a minute or two.
Because you’ve exhausted your lifetime quota of double posts? 
It seems to happen when you click Submit, and the board is balky at just that moment (just itching to give you one of them thar 50x errors), but you get impatient waiting and click Submit again. From what I can tell, when that happens, the first Submit does in fact get posted, and then the second Submit gets posted again, bypassing the double-posting check.
In fact, what I described above just happened while posting a typo fix to that post: I clicked “Save Changes”, waited [del]patiently[/del] impatiently but did not click “Save Chanes”, and got that 500-something error. Then I re-opened the thread, and sure enough, the fix was in.
For hours today I was told my name and/or password were wrong. When I just trued to comment, I got logged out. AGAIN.
It’s getting really bad now. I would suggest that the owners get some IT folks – good ones – and analyze what’s going on.
Now I’m getting “502 Server Error” when I click on threads I want to read, not just when I try to post. Thanks for asking management to look into this, TubaDiva.
Is management IT, or do you have to ask management to ask IT to look into it?
I’ll mention it to management. Again.
Jenny
your humble TubaDiva
Administrator
Seems to correlate with my usage of the board 
Every time I start previewing a post, the entire board starts timing out.
Pretty much that, I think; except that I wouldn’t put it so much to impatience, as that when I got the error I used to assume that the post I was trying to make hadn’t gone through. I’ve learned to doublecheck first, when the board’s working again, and have found that most of the time it has already posted.
It’s been happening that way for me all along – not only when I try to post, but also when I click on a thread to read it, or try to refresh a thread to check for new posts. Sometimes it’s 502, sometimes 504, sometimes ‘try again in 30 seconds’. Sometimes there are a lot of such errors in a particular day, sometimes none for days or even weeks. It comes and goes. The last few days have been a lot-of-errors stretch; though it hasn’t happened yet today (though I haven’t been on much yet today.)
I haven’t gotten any today. Maybe something got fixed.
I got a 504 earlier today.
None today yet, but I had been seeing them with some consistency over the past two weeks. Can’t pinpoint it to a certain time of day. I can say the 504 errors were noticeably more common immediately after submitting a post than after any other board activity.
As errors go, the SDMB 504 errors are pretty mild – they clear up every time after hitting Refresh.
EDIT: Forgot to give my browser/system specs:
Windows 7 Professional
Service Pack 1
Google Chrome
Version 60.0.3112.113 (Official Build) (32-bit)
The part in red seems to be common in message-board software: if you submit a post, and the page subsequently cannot load to your browser … 99 times out of a 100, that post did get entered into the message board’s database. It’s just a display issue, not a post-intake issue.
Time outs are really bad today.
I would not mind chipping in some money to get a better server or software or both. It is getting really bad.
I give up. Board is nigh unusable today.
Somebody, please send me a postcard when it works again.
Yeah, and it’s happening to me so frequently in the past few days that I now open the Dope in a second window just to see what’s happened since the first window timed out on me.
Of course, if the problem is the servers are somehow being overloaded, what I’m doing isn’t helping matters any.
Now I’m being told I have to wait sixty seconds between posts.
Yeah, that’s pretty much standard. Unless you haven’t posted anything in over a minute.