Unable to edit own comment in a blog

I am trying to correct a typing mistake in https://blogs.sap.com/2017/12/18/chatbots-will-drive-the-future-of-workplace-efficiency/comment-page-1/#comment-403170

The link from the edit option is: https://blogs.sap.com/wp-admin/comment.php?action=editcomment&c=403170

After pressing the button 'Update Comment" I encounter this message:

I was not logged out. I already tried logging out, closing the browser, clearing all data (I use private browsing mode by default, anyway).

I encounter the same error message in Firefox ESR 52.5.2, Firefox 57.0.2, Pale Moon 27.6.2, Google Chrome portable 63.0.3239.84 and IE11 (Windows 7, 32-bit)

My user is not a moderator (I do not know if this makes any difference).

I have encountered this problem before, but I attributed it at that time to the existence of subsequent comments - in this example there are none.

Would somebody with user authorizations similar to mine check for what browser/OS combination editing own comments in blogs does not result in such error and help me figure out what settings I need to adjust on my end, please?

In the web console I see as response to https://blogs.sap.com/wp-admin/admin-ajax.php : You are posting comments too quickly. Slow down.

If this is indeed the reason why I cannot edit my own comment - the first problem is that the error message that I see (from the first screenshot) does not correspond to the root cause, which makes it useless.

The second problem (assuming that the response in the web console may be the correct one) - I have absolutely no idea how long time should pass between edit attempts so that I can submit an edited the comment - 5 minutes, an hour, a day?