We are using Visual SVN server in our company. It worked well

But users unable to create particular branch from trunk folder

i have put svnadmin verify to check repository

i found error as below

* Verified revision 508448.
* Verified revision 508449.
* Verified revision 508450.
* Verified revision 508451.
svnadmin: E160004: Mergeinfo-count discrepancy on 'a-1.0.r508452/9674': expected
 1244741480414057964+0, counted 116

Could you please tell me what to do