Unable to file gstr-3b

Hi,

I have filed GSTR-3B for the month of July in August. I received ARN after filing GSTR-3B. However I gave inward supplies information under inward supplies for reverse charge. I couldn't amend it once I have filed. Now when I am trying to submit GSTR-3B for the month of August, it is asking me to submit GSTR-3B for July first which I have already filed. When I checked GSTR-3B for July, it shows it was not filed. So I tried to make change, save and submit but it was giving me an error message unable to save. I have tried to submit without making any changes, even then I am getting error message saying unable to submit GSTR-3B. What shall I do to file my GSTR-3B for July. Appreciate if anyone could help me regarding this issue. Regards