The log appears above the test result, you're confusing the error message of one test with the log of the next one.

-50 should equal -1275

The failing test is above, not below.

Read the description properly:

find the sum of all the integers between including them too and return it

So sum of numbers in the range of, and including, a and b.

False should equal True
Mean that your function returned False while the test is expecting True

Also, the log for a given test appears in a box before the colored test result (at leat on my browser) so my guess is that it is in the previous test that your function is returning False while the test is expecting True.

https://github.com/codewars/codewars.com/wiki/Troubleshooting-your-solution#print-input

might be helpfull

Would you mind to be more precise ?
Which language ?
Describe the test : what result did you expect ? what result did the test expect ?