Fixing POST Request Issue on Signzy Website

I'm having an issue specifically related to data not being submitted via the POST request from the Signzy website. I'm looking for a skilled freelancer with hands-on experience in backend development and API integration to help me resolve this issue.

Key requirements:
- Solid experience with backend development
- Proficiency in API integration
- Proven track record of resolving similar data submission problems
- Dedicated to troubleshooting and problem-solving
- Excellent communication skills

Successful applicants should focus on their relevant experience and how they can solve the issue efficiently and effectively.