Connecting to Dropbox is not possible // IpadOS 14.2

Hallo everybody, 

I have some problems opening documents from Dropbox. 

I am using Dropbox and Adobe acrobat reader on my IPad with IPadOS 14.2 

My usually workflow is that I go into Dropbox searching for my document I want to open. The next step is to press on the implemented button in Dropbox where a window opens where I can press on "open with Adobe acrobat reader".
After this process the application is opening but than the error report "connecting to Dropbox in not possible" in german: "Verbindung zu Dropbox nicht möglich" occurs. 
The curious about this is that if I repeat the process from the step "Open with Adobe acrobat reader" it is working on the second try. 
Thats really annoying. 

Does anybody have the same problem or even have a solution for the behavior? 

Thank you for your reply. 

Best regards