Error 526 when uploading MP4 to LinkedIn and Pabbly Upload File

Hello,

We are experiencing a persistent Error 526 when Pabbly Connect tries to process an MP4 file.

The issue occurs in two places:

1. When publishing a video to LinkedIn through Pabbly Connect.
2. When using the Pabbly "Upload File" action with the same MP4 URL.

Example MP4 URL:

https://api.m4w.pl/ugc/4.mp4

We have thoroughly tested the file and our hosting server.

The file is publicly accessible and returns the correct HTTP headers:

• HEAD request: HTTP 200 OK
• Content-Type: video/mp4
• Content-Length: 2,824,659 bytes
• Accept-Ranges: bytes
• HTTPS/SSL works correctly

We also tested a Range request:

• GET with Range: bytes=0-1023
• Server correctly returns HTTP 206 Partial Content
• Correct Content-Range header is returned

The important part is that our hosting provider checked the server logs for the exact time when Pabbly returned Error 526. They confirmed that there was no incoming connection or request to api.m4w.pl at that time.

This suggests that the error occurs on the Pabbly side before Pabbly actually attempts to connect to or download the MP4 file from our server.

The same URL works correctly when accessed directly and when downloaded using cURL.

Could you please check the Pabbly-side logs for this request and verify why Error 526 is being generated before any connection reaches our server?

This is currently preventing us from publishing MP4 videos to LinkedIn through our workflow.

Thank you.

Hello there,

Thanks for contacting us.

Could you please share the Workflow URL so that we can look into it and provide information accordingly?

Please be aware that to assist you effectively, we may need to access your Pabbly Connect account. If you're comfortable with this, please grant us permission by stating in your next email: "You have my permission to log into my Pabbly Connect account, and edit workflow {If required}. Here is the registered email address associated with it."

https://connect.pabbly.com/workflow/mapping/IjU3NjYwNTZjMDYzMDA0MzQ1MjZjNTUzYzUxM2Ii_pc

Hello,

I already provided the Workflow URL and granted permission for your support team to access my Pabbly Connect account when I created this thread.

Are you unable to see the information and permissions that I provided when submitting the original post?

Please let me know if I need to provide them again here in the reply.

Thank you.