Electronically signed documents

Considering the log file you shared,

[0702/131255.889:ERROR:context.cc(151)] The cache_path directory (C:\Users\Mi�osz Rychlewicz\AppData\LocalLow\Adobe\AcroCef\DC\Acrobat\Cache) could not be created.
[0702/131255.899:ERROR:context.cc(166)] The cache_path is invalid. Defaulting to in-memory storage.
[0702/132506.202:ERROR:context.cc(151)] The cache_path directory (C:\Users\Mi�osz Rychlewicz\AppData\LocalLow\Adobe\AcroCef\DC\Acrobat\Cache) could not be created.
[0702/132506.213:ERROR:context.cc(166)] The cache_path is invalid. Defaulting to in-memory storage.

there indeed appears to be a shortcoming in Acrobat in respect to paths with interesting characters.

BUT in the end Acrobat in the log excerpt switched to in-memory storage. Thus, these errors should not cause validation issues, should they?

@miłosz_6545 it sounds like a font issue or a charcter encoding mismatch. 

You could try this work-around, create a simple folder. On your C: drive (or any drive), create a new folder with a very simple name, like C:\TempPDFs or C:\PDFDocuments. Avoid any special characters, spaces, or non-ASCII characters in this folder name. Before opening the electronically signed PDF, copy or move it into this newly created simple folder (e.g., C:\TempPDFs\YourSignedDocument.pdf or C:\PDFDocuments\YourSignedDocument.pdf ). Now, open the PDF document directly from this simple folder. 

1. When you open the document from C:\TempPDFs or C:\PDFDocuments , Adobe Acrobat (and the underlying Windows processes it uses for signature verification) will primarily interact with this simplified path, avoiding the complex characters in your user profile directory. This can often prevent the encoding conflict that leads to the verification error.
   
   Let me know how it goes.