The Error: The word "consequency" is not a standard English adverb.
The Correction: The correct word to use here is consequently.
Grammar Rule: In this sentence, we need a conjunctive adverb to show the result of the first clause (the project being delayed).
Consequence is a noun.
Consequently is the adverbial form used to mean "as a result."
Punctuation Note: Notice the semicolon (;) before "consequently" and the comma (,) after it. This is the standard way to join two independent clauses using a conjunctive adverb.
Other parts are correct:
The project was delayed: Correct use of the passive voice.
because of unforeseen issues: "Because of" is correctly used followed by a noun phrase.
to adjust our timeline: Correct infinitive phrase ("to" + verb).
