I did find a solution to the problem. After reading through previous posts on this same subject, it said that the problem was solved by making sure there was text in the description area.
I also found that one of my tables had too many columns.
Once I removed the table with the large number of columns and added descriptors to the other tables, I was able to save the tables.
But that leaves the question, if a table is too large, what is too large? And if one table is too large, why does it cause a problem with every other table not being able to be saved?
Are there a specific number of columns and rows that are allowed in a table?
Thank you for your assistance and suggestions. I did not deactivate plugins and change the theme, I deleted the large table and that found the first half of the problem. Reading previous posts gave me the second half to fix this issue.