In your data file, you should search for and check the group with the cluster ID "26". All people within group # 26 (and other groups) should have the same values on your between level variables (blm, edb). If that is not the case, then there could be an error in your data. There may be additional groups (clusters) with the same issue that Mplus doesn't list.

Thank you Sir, for your quick response. I am following your book to run multilevel modeling using Mplus and as well as your videos too.. these are really helpful.. As i am very new to conduct multilevel modeling and running mplus, I can't understand how to check group with cluster ID. I am using SPSS to make .dat file for mplus... My question is ,"is there any procedures to check group with cluster ID or any other error in dataset using SPSS, please?" Thank you...

I would look in the SPSS data file. In SPSS, go to the variable named "group" in your Mplus VARIABLE NAMES list. Find the group that is coded "26" and see if there are members of that group that have differet values on the variables blm and/or edb. If blm and edb are truly between-level variables, there should not be any differences in the values of these variables for members of the same group (cluster). If you find differences, you need to figure out whether this is a data error or other issue that needs to be corrected/addressed.

It's done..! I'm incredibly grateful for your support, Sir...