Thank you for your reply,

I contacted my hosting provider and that was not the problem.
But we did find out what it was and here it is for future reference of anyone running into the same problem.
All I had to do was to increase the memory limit which was way too low.
Everything works fine now.
You can close this topic now and consider it resolved.

Thanks again.

Thank you for your reply!

The problem if I do this (and I have already tried it), is that then I lose the portfolio category sorting I need.

I would be able to choose the ‘City’ (tag taxonomy) but I would not be able to use ‘Service Category’ (category taxonomy).
So a website visitor would be able to choose NY but then he would be presented with all NY’s ‘Professionals’ without being able to sort them by the ‘Services’ provided.

I hope this is more clear on my part. If I am missing something please let me know.

For one more time thank you for your effort.