Others ⇒ When using babel package getting error in ! Extra }, or forgotten \endgroup. <argument> ...box {\NAT@@close }\fi \NAT@@c

[craju2000]

Hi,
I am using babel.sty package in the tex file, while compiling getting below error

! Extra }, or forgotten \endgroup.
<argument> ...box {\NAT@@close }\fi \NAT@@close }}

Herewith, I have attached zip file contains tex file, bib file, class file, NJDnatbib style, etc.

Could you please help me to resolve this issue. When using general natbib.style the error will not occurred. However, when using NJDnatbib style then the errors throw in \citation command.

Please kindly help me to resolve the issue.

Thanks
CRAJU200