Webviewer not showing some sites on one machine

[normanicus]

We are having a hard time solving a problem involving one Mac (High Sierra) running Filemaker 17 (Advanced tools enabled).

There is  a webviewer which displays a page depending on the URL in a field. This has been working for years. The client has three Macs, all running FM17 and using FM17 Server. On two of the machines the pages show as normal. On the client's own machine the page does not show. Activity can be seen in the bottom bar of the webviewer as if the page is loading and, sometimes, one sees the URL flash up there. He has gone back to using FM16 as that works normally.

This gets stranger. After many attempts to get to the root of this I put URLs from other sites into the 'Custom' box. These pages displayed correctly. I chose  Google Maps (UK) and put a place in the box. Again, this displayed as normal.

Reinstalled Filemaker 17. Problem still there.

Copied the layout and pasted it a a new layout. Didn't work. I recreated the webviewer. No go.

I'm sure we tried all kinds of other things to no avail. I have left him with the suggestion of installing FM17 on another Mac and logging in the Filemaker to see if that works. I suspect it will. Which will mean that there is an interaction between something on his computer and Filemaker which is not showing on other machines.

My memory told me of log files that got to big and caused a problem. That was way back and I can find no log files for Filemaker on his machine.

His company has recently moved the site from Magento 1.8 to Magento 2.xx so everything was redone. The only significant difference I can think of in relation to this is that he does most of the importing and exporting of products and stuff ie his webviewer has a lot more stuff pass through it. So, if there were to be an overfull log file it would be on his computer it would show. However, this doesn't fit with URLs from pages not on his site working normally.

Has anybody else had this happen? Any ideas?

Thank you if you got this far.

PS He did the install on a Mac Mini and it worked as it should.

Forgot to say: tried changer the default browser. No change. 

 

Edited November 23, 2018 by normanicus
More information came to light.