We reprove Proposition 3.8 in our paper that was published in [Electron. J. Qual.
Theory Differ. Equ. 2021, No. 7, 1-24], to fill a gap in the proof of Corollary 3.7
where the density of one of the embeddings does not follow by the original arguments.
We further carry out some minor corrections in the proof of Corollary 3.7, in Remark
3.1 and in the formula (3.23) of the original paper.