Alert – Unauthorized access (invalid token)

Hi! First of all, thank you for your amazing plugin!

I did a setup with 2 Sites, and the main site can write properly to the 2nd site, but the second site cannot write data to the main site.

Both site are responding with HTTP200 and working fine.

Plugin writes in log on Main site, test pushed from 2nd site:

2022-01-12 21:46:49 – Success – Ping success for action “Metadata” from https://site2.com with remote IP XX.XX.XX.XX (incoming)
2022-01-12 21:49:01 – Info – Token created: site https://www.site1.at – action “Login”
2022-01-12 21:49:02 – Alert – Unauthorized access (invalid token) – https://site2.com

Plugin writes in log on Second Site, test pushed form 2nd site:
2022-01-12 21:30:10 – Info – Renewing token for https://www.noyoga.at
2022-01-12 21:30:11 – Alert – Error contacting the remote site: Payload error – Syntax error
2022-01-12 21:30:11 – Info – Response data received from the remote site:

Payload Error is what i get as response on the 2nd site when performing tests and main site says: “Unauthorized Access – “invalid token”

Tried different setups, checkt everything, and still no clue.
Any idea? Thank you a lot!!!!