I am unable to sign in to my FamilySearch account because of the above
You can often solve the problems by reset Familysearch Cookies. Cookies are small pieces of code that FamilySearch and other websites store on your computer. Using cookies allows FamilySearch to customize your experience for you. Go to https://familysearch.org/cookies
You could also try a different internet browser and see if you have the same problem.
Lastly, contact FamilySearch support for help. https://www.familysearch.org/en/fieldops/familysearch-support-contact-us