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Could you provide more detailed information to what exactly is happening, any error message and steps to reproduce? Also the screenshot is really small. Can you provide a larger image for the issue? 
POST /oauth2/token
Application ID sq0idp-mqruPpwl3vDf-JN_r-f8vg
Trace ID CDN-207e884f-ae21-412f-ab36-c3f3cde192d5
“message”: “internal server error”,
“type”: “internal_server_error”
Is there a reason your creating so many refresh tokens for the authorization?
Ok what is an optimal frequency you suggest for refreshing tokens 
Once per week? Once per month?
Because I see no “rate limit” or “frequency limit” got mentioned by the doc so I got confused.
Also can you verify that the root cause of square internal server error is due to creation of too many refreshing tokens?
If so, when will I gain access to new refresh tokens again?