Thank you for the shared details.
Probably any of the elements is not located on the page and the Assert statement is failing. You could double check the execution log
where further details will be listed about the exception thrown.
Since you need to use code to automate your actions I would like to share with you what methods you could use to locate elements on page
. Please note we do not recommend using Xpaths as these might be easily changes with a minor update in the application under test.
Another useful advice will be to insert Assert statements
after each line where you locate an element - that way you will easily find out which is the element which is not properly located.
In addition I noticed that the Xpaths visible partially are both relative to a grid which contains the html table. If you are locating the table cell under the html table you probably need to change that Xpath as well. Of course, if you decide to stick to Xpath usage.
I hope the information will be useful to you. Though let me know in case of further questions.