PJ Foley

Looking into this further–more details:
I’m using Amazon SES for sending. It’s working well, but I needed to fix an issue with my bounce address not being authorized by Amazon SES. That has since been fixed, and yet I still get the error “Error occurred, unable to check connection.” no matter what combination of servers/security/ports available to me.

The error messages come up faster now–before the authorization of the address, this took a while. So it seems like the errors may be more “normal” now, but the error persists.

Had the same problem–Looks like it just got an update and it’s working for me now.

I should also note that SiteGround has been able to get me back to the state where I can work in the Admin section, but WordPress fixes are (understandably) beyond the scope of their support.

Hello–I, too, have been having this frustrating problem, and none of the above fixes have helped. Bear with me on the details:
I’ve been trying to use a staging site to test various upgrades of plugins, themes, and WordPress itself. I’m using SiteGround as my hosting, and usually this is a rather painless and straightforward process. However, this has become a showstopper.
I have similar results as described above.
Workarounds that work include changing Permalinks to the default or making the start page ‘Posts’ rather than ‘A Page’
However, none of those are acceptable due to our existing links and search result pages, etc.
my URL settings do not have capital letters in it.
I can get to admin pages by setting my HOME and BASE urls in my wp-config. I can also change these in the database and get to admin pages fine.
Possible hints:
If I try to change the base and home within Settings->General, they will not stick.
Redoing Permalinks (by saving changes) has no effect.
I’ve messed with redirects and DNS entries and have not been able to improve any result.
Disabling all plugins and going to a base theme (TwentyFifteen, etc) does not change this.
One more hint: my main site is https, but my staging site is avoiding it as it’s not officially supported.
changing or deleting .htaccess does not help
changing PHP versions does not help.
This leads me to believe that this is definitely something within wordpress.
Is this a case of “don’t update to 4.5.1 until 4.5.2”???
This has been vexing me since the release and stopping me dead in my efforts to upgrade.